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Which animal's feet are also adapted for sticking to smooth surfaces?

s live in the rain forests of Indonesia. They spend most of their lives in trees. The feet of the are adapted to stick to the smooth surfaces of leaves. Figure: Borneo eared frog.

closed choice

grade3

natural science

biology

Adaptations

Animal adaptations: feet and limbs

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The shape of an animal's feet is one example of an adaptation. Animals' feet can be adapted in different ways. For example, webbed feet might help an animal swim. Feet with thick fur might help an animal walk on cold, snowy ground.

Look at the picture of the Borneo eared frog. The Borneo eared frog has wide, sticky toes. Its feet are adapted for sticking to smooth surfaces. The Borneo eared frog uses its toes to walk on the smooth surfaces of leaves without slipping. Now look at each animal. Figure out which animal has a similar adaptation. The tiger-striped leaf frog has wide, sticky toes. Its feet are adapted for sticking to smooth surfaces. The American alligator has short toes with claws. Its feet are not adapted for sticking to smooth surfaces.

Which of these cities is marked on the map?

closed choice

grade5

social science

geography

Cities

Cities of the Midwest

The city is Omaha, Nebraska. Cleveland, Milwaukee, and Indianapolis are marked with gray circles on the map below.

What is the capital of Minnesota?

closed choice

grade5

social science

geography

State capitals

Identify state capitals of the Midwest

Saint Paul is the capital of Minnesota.

Which text uses the word can in its traditional sense?

closed choice

grade12

language science

writing-strategies

Word usage and nuance

Explore words with new or contested usages

Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.

The second text uses can in its traditional sense: to have the ability to. Gina can type using a keyboard with a QWERTY layout, but she prefers the Dvorak layout. The two keyboards have different arrangements of letters and symbols. The first text uses can in its nontraditional sense: to have permission to. If Gina prefers a keyboard with the Dvorak layout, she can use mine. In my opinion, it's faster than typing on a keyboard with a QWERTY layout. Most style guides recommend to use the traditional sense of the word can because it is considered more standard.

Which of the following organisms is the secondary consumer in this food web?

Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada. A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

closed choice

grade6

natural science

biology

Ecological interactions

Interpret food webs I

A food web is a model. A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food. Arrows show how matter moves. A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating. An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web. An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Secondary consumers eat primary consumers, and primary consumers eat producers. So, in a food web, secondary consumers have arrows pointing to them from primary consumers. Primary consumers have arrows pointing to them from producers. The snowy owl has an arrow pointing to it from the short-tailed weasel. The short-tailed weasel is not a primary consumer, so the snowy owl is not a secondary consumer. The parasitic jaeger has an arrow pointing to it from the brown lemming. The brown lemming is a primary consumer, so the parasitic jaeger is a secondary consumer. The short-tailed weasel has an arrow pointing to it from the brown lemming. The brown lemming is a primary consumer, so the short-tailed weasel is a secondary consumer. The brown lemming has arrows pointing to it from the bilberry and the bear sedge. Neither the bilberry nor the bear sedge is a primary consumer, so the brown lemming is not a secondary consumer.

Which is a compound sentence?

closed choice

grade3

language science

grammar

Sentences, fragments, and run-ons

Is the sentence simple or compound?

A simple sentence is a sentence with only one subject and predicate. The pitcher threw the ball to first base. A compound sentence is two simple sentences joined by a comma and a conjunction such as and, but, or, or so. The pitcher threw the ball, and the batter hit it. Some simple sentences have a compound subject or a compound predicate, but they are not compound sentences. Anna and James will watch the fireworks tonight. This simple sentence has a compound subject, Anna and James. The singers bowed and walked off the stage. This simple sentence has a compound predicate, bowed and walked off the stage. Some simple sentences have introductory phrases, but they are not compound sentences. The introductory phrase is part of the predicate. In the winter, Farmer Ben wears his heavy coat. This is a simple sentence. There is one subject, Farmer Ben, and one predicate, wears his heavy coat in the winter.

The first sentence is the compound sentence. It is made up of two simple sentences joined by a comma and the conjunction but. We have a spare tire, but it is flat, too.

Which word would you find on a dictionary page with the following guide words? scenery - social

closed choice

grade7

language science

reference-skills

Reference skills

Use guide words

Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.

Put the words in alphabetical order. Since smuggle is between the guide words scenery - social, it would be found on that page.

Which greeting is correct for a letter?

closed choice

grade4

language science

punctuation

Formatting

Greetings and closings of letters

A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory

The second greeting is correct: Its first word is capitalized, and it ends with a comma. Uncle Tom is capitalized because it is a proper noun.

Would you find the word rumble on a dictionary page with the following guide words? remote - rob

yes or no

grade8

language science

reference-skills

Reference skills

Use guide words

Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.

Put the words in alphabetical order. Since rumble is not between the guide words remote - rob, it would not be found on that page.

Is baryte a mineral or a rock?

Baryte has the following properties: not made by living things yellow fixed crystal structure found in nature solid pure substance

closed choice

grade8

natural science

earth-science

Rocks and minerals

Identify rocks and minerals

Minerals are the building blocks of rocks. A rock can be made of one or more minerals. Minerals and rocks have the following properties: Property | Mineral | Rock It is a solid. | Yes | Yes It is formed in nature. | Yes | Yes It is not made by organisms. | Yes | Yes It is a pure substance. | Yes | No It has a fixed crystal structure. | Yes | No You can use these properties to tell whether a substance is a mineral, a rock, or neither. Look closely at the last three properties: Minerals and rocks are not made by organisms. Organisms make their own body parts. For example, snails and clams make their shells. Because they are made by organisms, body parts cannot be minerals or rocks. Humans are organisms too. So, substances that humans make by hand or in factories are not minerals or rocks. A mineral is a pure substance, but a rock is not. A pure substance is made of only one type of matter. Minerals are pure substances, but rocks are not. Instead, all rocks are mixtures. A mineral has a fixed crystal structure, but a rock does not. The crystal structure of a substance tells you how the atoms or molecules in the substance are arranged. Different types of minerals have different crystal structures, but all minerals have a fixed crystal structure. This means that the atoms and molecules in different pieces of the same type of mineral are always arranged the same way. However, rocks do not have a fixed crystal structure. So, the arrangement of atoms or molecules in different pieces of the same type of rock may be different!

Baryte has all the properties of a mineral. So, baryte is a mineral.

Which country is highlighted?

closed choice

grade8

social science

geography

Oceania: geography

Identify and select countries of Oceania

This country is Vanuatu. Does Vanuatu have any territorial disputes? Vanuatu claims to own Matthew and Hunter Islands, which are disputed islands. In other words, multiple countries or groups claim that the islands rightfully belong to them. France has controlled the islands since 1929. But shortly after gaining independence in 1980, Vanuatu claimed to rightfully own the islands. It points to underwater geographic features and legends passed down by its people to argue that it has stronger connections to the islands than France. No one lives on the islands today.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade6

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

Each particle in the two samples has the same mass, but the particles in sample A have a higher average speed than the particles in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

Which closing is correct for a letter?

closed choice

grade3

language science

punctuation

Formatting

Greetings and closings of letters

A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory

The first closing is correct: Its first word is capitalized, and it ends with a comma.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade8

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

The particles in both samples have the same average speed, but each particle in sample A has more mass than each particle in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B. Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.

Which is smoother?

closed choice

grade2

natural science

physics

Materials

Compare properties of materials

Every object is made of one or more materials. A material is a type of matter. Wood, glass, metal, and plastic are common materials. A material has different properties. A material's properties tell you how it looks, feels, tastes, or smells.

Smooth is a property. A smooth material is not rough or bumpy. Look at each picture, one at a time. Imagine touching the material shown in each picture. Of the choices, the linen handkerchief is smoother. If you touch linen fabric, it will not feel rough.

What is the capital of North Carolina?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Southeast

Raleigh is the capital of North Carolina.

Which is a complex sentence?

closed choice

grade5

language science

grammar

Sentences, fragments, and run-ons

Is the sentence simple, compound, or complex?

A clause is a group of words that contains both a subject and a predicate. An independent clause is a complete thought. It can stand alone as a sentence. A dependent clause is not a complete thought. It cannot stand alone as a sentence. the oranges on our tree are ripe The clause can stand alone. It is independent. after we pick up Kevin from work The clause cannot stand alone. It is dependent. A simple sentence is made up of a single independent clause. Ben and I spent all day relaxing by the pool. Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate. In the winter, Ben usually wears his heavy coat. Ben usually wears his heavy coat in the winter. A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so. We saw a flash of lightning, and seconds later we heard the rumble of thunder. A complex sentence is made up of an independent clause and a dependent clause. The dependent clause usually begins with a subordinating conjunction such as after, although, as, because, before, if, since, unless, until, when, or while. If she ever gets the chance, Terri would love to visit the Egyptian pyramids.

The first sentence is the complex sentence. It is made up of an independent clause and a dependent clause. The dependent clause begins with the subordinating conjunction after. After Patty returned from the Galápagos Islands, she showed Scott and Norma pictures of all the exotic animals.

Based on this information, what is this tomato plant's genotype for the fruit texture gene?

In a group of tomato plants, some individuals have smooth fruit and others have fuzzy fruit. In this group, the gene for the fruit texture trait has two alleles. The allele F is for smooth fruit, and the allele f is for fuzzy fruit. A certain tomato plant from this group has smooth fruit. This plant has two alleles for smooth fruit.

closed choice

grade7

natural science

biology

Genes to traits

Genetics vocabulary: genotype and phenotype

All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.

An organism's genotype for a gene is its combination of alleles for that gene. The tomato plant has two alleles for smooth fruit (F). So, the plant's genotype for the fruit texture gene is FF.

Last year, there were seven men's clothing stores on Main Street in Stafford. This year, there are only three. What probably happened to the overall supply of men's shirts in Stafford?

closed choice

grade7

social science

economics

Supply and demand

Understand overall supply and demand

Overall supply is the total amount of a good or service that producers make and sell. There are several things that can make overall supply go up or down. The table below shows how changes to these things might affect overall supply. | Resources | Number of producers or suppliers | Expected change in demand Supply goes up | when resources cost less or are easier to get | when there are more producers or suppliers | when demand is expected to go up Supply goes down | when resources cost more or are harder to get | when there are fewer producers or suppliers | when demand is expected to go down Producers are people or companies that make goods or provide services. Suppliers are people or companies that sell goods or services. New inventions or technologies can also help workers produce goods and services more quickly. As a result of these changes, the supply of a good or service will often go up.

When four men's clothing stores closed on Main Street, the number of suppliers went down. There were fewer stores selling men's shirts. So, the supply of men's shirts probably went down.

Identify the question that Camille's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Camille planted 25 tomato seeds one-half inch below the soil surface in each of six pots. Camille added an equal amount of fertilizer to three of the six pots. She placed the pots in a plant growth chamber where all the seeds experienced the same temperature, amount of light, and humidity level. After two weeks, Camille counted the number of seedlings that grew in each pot. She compared the number of seedlings in the pots with fertilizer to the number of seedlings in the pots without fertilizer. Figure: tomato seedlings growing in soil.

closed choice

grade6

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

Judaism (JU-dee-izm) is a religion that has existed for thousands of years. What are people who practice Judaism called?

closed choice

grade6

social science

world-history

World religions

Origins of Judaism

Today, people who practice Judaism, or actively follow its teachings and traditions, are called Jews. But there are also many Jews who don't take part in religious practices. These people may still think of themselves as Jews because of their ancestry, or family history. Early in Jewish history, ancestors of the first Jews were known as Hebrews and then Israelites.

Does this passage describe the weather or the climate? Chad noticed that the sky was filled with cumulus clouds every day last week.

Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.

closed choice

grade3

natural science

earth-science

Weather and climate

What's the difference between weather and climate?

The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.

Read the text carefully. Chad noticed that the sky was filled with cumulus clouds every day last week. This passage tells you about the clouds Chad saw last week. It describes the atmosphere at a certain place and time. So, this passage describes the weather.

What does the idiom in this text suggest? "Speak of the devil!" Shelley declared when Kenji strolled into the room.

closed choice

grade8

language science

figurative-language

Literary devices

Interpret figures of speech

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. An idiom is an expression that cannot be understood literally. Its meaning must be learned. The assignment was a piece of cake.

The text uses an idiom, an expression that cannot be understood literally. The idiom speak of the devil suggests that Shelley had just been speaking about Kenji. People say this when the person they've just been speaking about coincidentally arrives, as if summoned.

Which animal's skin is also adapted for survival in cold places?

s live in the Canadian Arctic and Greenland. The 's skin is adapted to help the animal survive in cold places. Figure: Arctic hare.

closed choice

grade3

natural science

biology

Adaptations

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Look at the picture of the Arctic hare. During the winter, the Arctic hare has thick fur covering its skin. Its skin is adapted for survival in cold places. The Arctic hare uses its fur to keep warm in cold weather. Now look at each animal. Figure out which animal has a similar adaptation. The polar bear has skin with thick fur on top and a thick layer of fat underneath it. Its skin is adapted for survival in cold places. The fantastic leaf-tailed gecko has thin skin covering its body. Its skin is not adapted for survival in cold places.

Which tense does the sentence use? Molly will exercise with Owen in the morning.

closed choice

grade4

language science

verbs

Verb tense

Is the sentence in the past, present, or future tense?

Present tense verbs tell you about something that is happening now. Most present-tense verbs are regular. They have no ending, or they end in -s or -es. Two verbs are irregular in the present tense, to be and to have. You must remember their forms. Past tense verbs tell you about something that has already happened. Most past-tense verbs are regular. They end in -ed. Some verbs are irregular in the past tense. You must remember their past-tense forms. Future tense verbs tell you about something that is going to happen. All future-tense verbs use the word will. Present | Past | Future walk, walks | walked | will walk go, goes | went | will go

The sentence is in future tense. You can tell because it uses will before the main verb, exercise. The verb tells you about something that is going to happen.

Compare the motion of three cars. Which car was moving at the lowest speed?

closed choice

grade3

natural science

physics

Force and motion

Compare the speeds of moving objects

An object's speed tells you how fast the object is moving. Speed depends on both distance and time. Distance tells you how far the object has moved. One unit used to measure distance is the mile. Time tells you how long the object has spent moving. One unit used to measure time is the hour. Think about objects moving for the same amount of time. The object that is moving the slowest will go the shortest distance in that time. It is moving at the lowest speed.

Look at the distance each car moved and the time it took to move that distance. The direction each car moved does not affect its speed. Notice that each car moved for 10 hours. The car that moved 140 miles moved the shortest distance in that time. So, that car must have moved at the lowest speed.

Which country is highlighted?

closed choice

grade8

social science

geography

Oceania: geography

Identify and select countries of Oceania

This country is Kiribati.

Which of the following could Jen's test show?

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below. Wind turbines use wind power to produce electricity. Jen was a materials engineer who designed wind turbines. She wanted to design a new turbine that would produce 10% more electricity than older wind turbines. She thought that a turbine made from lightweight material would turn more easily and produce more electricity. So, Jen created a computer model of a turbine made from lightweight material. Then she used the model to calculate how much more electricity the new turbine could produce compared to the older turbines. Figure: studying a wind turbine computer model.

closed choice

grade7

natural science

science-and-engineering-practices

Engineering practices

Evaluate tests of engineering-design solutions

People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. How can you determine what a test can show? You need to figure out what was tested and what was measured. Imagine an engineer needs to design a bridge for a windy location. She wants to make sure the bridge will not move too much in high wind. So, she builds a smaller prototype, or model, of a bridge. Then, she exposes the prototype to high winds and measures how much the bridge moves. First, identify what was tested. A test can examine one design, or it may compare multiple prototypes to each other. In the test described above, the engineer tested a prototype of a bridge in high wind. Then, identify what the test measured. One of the criteria for the bridge was that it not move too much in high winds. The test measured how much the prototype bridge moved. Tests can show how well one or more designs meet the criteria. The test described above can show whether the bridge would move too much in high winds.

What do these two changes have in common? water evaporating from a puddle dry ice sublimating and becoming a gas

closed choice

grade8

natural science

chemistry

Chemical reactions

Compare physical and chemical changes

Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.

Step 1: Think about each change. Water evaporating from a puddle is a change of state. So, it is a physical change. The liquid changes into a gas, but a different type of matter is not formed. Dry ice is solid carbon dioxide. When dry ice gets warm, it changes state and becomes carbon dioxide gas. This change of state, from solid to gas, is called sublimation. Dry ice becoming a gas is a physical change. A change of state does not form a different type of matter. Step 2: Look at each answer choice. Both are only physical changes. Both changes are physical changes. No new matter is created. Both are chemical changes. Both changes are physical changes. They are not chemical changes. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.

Complete the sentence. A flower petal turning brown is a ().

closed choice

grade5

natural science

chemistry

Physical and chemical change

Compare physical and chemical changes

Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.

A flower petal turning brown is a chemical change. As the petal turns brown, the colorful matter in the petal breaks down and changes into a different type of matter.

Which of these states is farthest south?

closed choice

grade3

social science

geography

Geography

Read a map: cardinal directions

Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west. A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction. The north arrow points to the North Pole. On most maps, north is at the top of the map.

To find the answer, look at the compass rose. Look at which way the south arrow is pointing. Tennessee is farthest south.

What can Reggie and Wendy trade to each get what they want?

Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another. Reggie and Wendy open their lunch boxes in the school cafeteria. Neither Reggie nor Wendy got everything that they wanted. The table below shows which items they each wanted: Look at the images of their lunches. Then answer the question below. Reggie's lunch Wendy's lunch

closed choice

grade8

social science

economics

Basic economic principles

Trade and specialization

Look at the table and images. Reggie wants broccoli. Wendy wants tomatoes. They can trade tomatoes for broccoli to both get what they want. Trading other things would not help both people get more items they want.

Select the plant.

closed choice

grade3

natural science

biology

Classification

Identify plants and animals

Plants and animals are living things. Living things are called organisms. Plants come in many shapes and sizes. Most plants grow in the ground. They might grow leaves, flowers, and fruit. Plants cannot move around on their own like animals can. Animals also come in many shapes and sizes. Most animals can move around. Animals might run, swim, jump, or fly. Animals eat plants or other organisms for food.

A wombat is an animal. It eats plants. Wombats have strong claws. They use their claws to dig tunnels called burrows. A dung beetle is an animal. It walks and runs. Dung beetles eat animal waste, which is called dung. They roll the dung into balls to store for later. A dahlia is a plant. It can grow colorful flowers. Dahlia plants grow in the wild in Central America. But people grow dahlias in gardens all over the world! A wolf is an animal. It eats other animals. Wolves often live in family groups. A wolf family group is called a pack.

Which greeting is correct for a letter?

closed choice

grade4

language science

punctuation

Formatting

Greetings and closings of letters

A letter starts with a greeting and ends with a closing. For each one, capitalize the first word and end with a comma. You should also capitalize proper nouns, such as Aunt Sue. Dear Aunt Sue, I'm glad you could come to my party, and thank you for the birthday gift. I could not have asked for a better one! Every time I see it, I think of you. With love, Rory

The second greeting is correct: Its first word is capitalized, and it ends with a comma. Mrs. Erickson is capitalized because it is a proper noun.

Which of the following contains a vague pronoun reference?

closed choice

grade10

language science

writing-strategies

Pronouns

Identify vague pronoun references

When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent. When Lisa and Kim finally landed, she breathed a sigh of relief. The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear. Vague pronoun references can be corrected in one of two ways: 1. Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief. 2. Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed. A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent. They say that this nail polish dries in less than five minutes. The pronoun they is used without its antecedent, so the meaning of the sentence is unclear. This problem can be fixed by replacing the pronoun with its missing antecedent. The advertisements say that this nail polish dries in less than five minutes.

The first answer choice contains a vague pronoun reference. The pronoun she could refer to Jill or her sister. Jill told her sister that she couldn't go to the film festival because of final exams. The second answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear. Jill said that she couldn't go to the film festival with her sister because of final exams.

Is vinegar a solid, a liquid, or a gas?

closed choice

grade3

natural science

physics

States of matter

Classify matter as solid, liquid, or gas

Solid, liquid, and gas are states of matter. Matter is anything that takes up space. Matter can come in different states, or forms. When matter is a solid, it has a definite volume and a definite shape. So, a solid has a size and shape of its own. Some solids can be easily folded, bent, or broken. A piece of paper is a solid. Also, some solids are very small. A grain of sand is a solid. When matter is a liquid, it has a definite volume but not a definite shape. So, a liquid has a size of its own, but it does not have a shape of its own. Think about pouring juice from a bottle into a cup. The juice still takes up the same amount of space, but it takes the shape of the bottle. Some liquids do not pour as easily as others. Honey and milk are both liquids. But pouring honey takes more time than pouring milk. When matter is a gas, it does not have a definite volume or a definite shape. A gas expands, or gets bigger, until it completely fills a space. A gas can also get smaller if it is squeezed into a smaller space. Many gases are invisible. Air is a gas.

Vinegar is a liquid. A liquid takes the shape of any container it is in. If you pour vinegar into a different container, the vinegar will take the shape of that container. But the vinegar will still take up the same amount of space.

Which text uses the word nauseous in its traditional sense?

closed choice

grade12

language science

writing-strategies

Word usage and nuance

Explore words with new or contested usages

Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.

The first text uses nauseous in its traditional sense: causing disgust or nausea. Brooke couldn't tolerate the nauseous odor emanating from the landfill, so she rolled up her car windows as she drove past. The second text uses nauseous in its nontraditional sense: feeling disgusted or nauseated. The odor emanating from the landfill made Brooke so nauseous that she had to roll up the car windows as she drove past. Most style guides recommend to use the traditional sense of the word nauseous because it is considered more standard.

How long is a leather belt?

Select the best estimate.

closed choice

grade7

natural science

units-and-measurement

Units and measurement

Choose customary units of distance, mass, and volume

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. When you are using customary units, length may be written with units of inches, feet, yards, or miles. There are 12 inches in 1 foot, and 3 feet in 1 yard. There are 5,280 feet in 1 mile. A football is about 1 foot long. A football field is 100 yards long.

The best estimate for the length of a leather belt is 25 inches. 25 feet, 25 yards, and 25 miles are all too long.

What information supports the conclusion that Ava inherited this trait?

Read the description of a trait. Ava has brown eyes.

closed choice

grade3

natural science

biology

Heredity

Inherited and acquired traits: use evidence to support a statement

Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.

Which ocean is highlighted?

closed choice

grade7

social science

geography

Physical Geography

Oceans and continents

Oceans are huge bodies of salt water. The world has five oceans. All of the oceans are connected, making one world ocean.

This is the Southern Ocean. The Southern Ocean reaches from the shores of Antarctica to 60° South latitude.

Using only these supplies, which question can Malik investigate with an experiment?

Malik is painting watercolor pictures with his friend. An hour after they have finished, Malik notices one painting is dry but the other is not. He wonders what factors affect how quickly watercolor paintings dry. So, he decides to design an experiment. He has the following supplies available: two freshly painted watercolor pictures of the same size his dining room table a picnic table in his backyard a heater

closed choice

grade8

natural science

science-and-engineering-practices

Designing experiments

Identify questions that can be investigated with a set of materials

Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment. Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment? First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available. Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick. So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!

What does the verbal irony in this text suggest? "That fits you well," Ezra remarked after Anna's cap fell over her eyes for the tenth time.

closed choice

grade7

language science

figurative-language

Literary devices

Interpret figures of speech

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.

The text uses verbal irony, which involves saying one thing but implying something very different. Fits you well ironically suggests that the cap was too big. The cap was falling over Anna's eyes, so it didn't fit her well at all.

Which bird's beak is also adapted to tear through meat?

Turkey vultures are scavengers. They find and eat the bodies of dead animals. The shape of the 's beak is adapted to tear through meat. Figure: turkey vulture.

closed choice

grade4

natural science

biology

Adaptations

Animal adaptations: beaks, mouths, and necks

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks.

Look at the picture of the turkey vulture. The turkey vulture has a sharp hooked beak. Its beak is adapted to tear through meat. The sharp hook can help the turkey vulture cut the meat into pieces it can swallow. Now look at each bird. Figure out which bird has a similar adaptation. The red-tailed hawk has a sharp hooked beak. Its beak is adapted to tear through meat. The bufflehead has a wide, flat beak. Its beak is not adapted to tear through meat. The bufflehead uses its beak to eat plants and invertebrates that live in mud.

Does this passage describe the weather or the climate? June, July, and August are usually humid in New Orleans, Louisiana.

closed choice

grade5

natural science

earth-science

Weather and climate

What's the difference between weather and climate?

The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.

Read the text carefully. June, July, and August are usually humid in New Orleans, Louisiana. Humidity is the amount of water in the air. This passage tells you about the usual summer humidity in New Orleans. It does not describe what the weather is like on a particular day. So, this passage describes the climate.

Select the animal that has a backbone.

Hint: Mammals, birds, fish, reptiles, and amphibians all have backbones.

closed choice

grade2

natural science

biology

Classification

Identify animals with and without backbones

Some animals have a backbone. The backbone is made of many bones in an animal's back. An animal's backbone helps connect the different parts of its body. In the drawings below, each animal's backbone is colored orange. Other animals do not have a backbone. In fact, these animals don't have any bones! Some animals without backbones have a hard outer cover. Other animals have a soft body.

A pelican is a bird. Like other birds, a pelican has a backbone. A bumble bee is an insect. Like other insects, a bumble bee does not have a backbone. It has a hard outer cover.

Suppose Amanda decides to go on the pirate ship. Which result would be a cost?

Amanda is deciding which ride to go on at the fair. She can go on either the Ferris wheel or the pirate ship. She wants to have as much fun as possible at the fair.

closed choice

grade5

social science

economics

Basic economic principles

Costs and benefits

Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.

This result is a cost. It involves giving up or spending something that Amanda wants or needs: Amanda will give up the chance to go on the Ferris wheel. She would have had more fun on that ride.

Identify the question that Neil's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Neil used a dropper to put equal-sized drops of pure water, one at a time, onto a penny. The drops stayed together and formed a dome on the penny's surface. Neil recorded the number of drops he could add before the water spilled over the edge of the penny. Then, he rinsed and dried the penny, and repeated the test using water mixed with hand soap. He repeated these trials on nine additional pennies. Neil compared the average number of pure water drops to the average number of water drops mixed with hand soap that he could add to a penny before the water spilled over. Figure: a dome of water on the surface of a penny.

closed choice

grade7

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

Select the living thing.

closed choice

grade3

natural science

biology

Classification

Identify living and nonliving things

All living things need food and water. Water helps living things break down food and remove waste. Food gives living things energy. Living things use this energy to grow and change. All living things grow and change during their lives. All living things sense changes in the world around them. Living things might sense changes by seeing, smelling, hearing, or feeling. Living things can respond to the changes they sense.

A pushpin is not a living thing. Pushpins do not have all of the traits of living things. They do not grow or respond to the world around them. They do not need food or water. A robin is a living thing. Robins grow and respond to the world around them. They need food and water.

Which figure of speech is used in this text? When Mona first joined the track team, she was afraid of jumping, but she got over that hurdle.

closed choice

grade10

language science

figurative-language

Literary devices

Classify figures of speech: review

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Alliteration is the repetition of sounds at the beginning of nearby words. What a lucky little lady you are! An allusion is a brief reference to something or someone well known, often from history or literature. "I'd better get home before I turn into a pumpkin!" Lila remarked. An idiom is an expression that cannot be understood literally. Its meaning must be learned. The assignment was a piece of cake. A simile uses like or as to compare two things that are not actually alike. The cat's fur was as dark as the night. A metaphor compares two things that are not actually alike without using like or as. The snow formed a blanket over the town. Onomatopoeia involves using a word that expresses a sound. The scrambled eggs hit the floor with a splat. Personification is giving human characteristics to nonhuman things. The trees danced in the wind. A pun involves using a word or phrase in a humorous way that suggests more than one meaning. A great new broom is sweeping the nation. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.

The text uses a pun, a word or phrase that humorously suggests more than one meaning. Hurdle refers to an obstacle that one must overcome. It also refers to an object that a runner jumps over.

What is the capital of Missouri?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Midwest

Jefferson City is the capital of Missouri.

Which trait did Glyphithyreus have? Select the trait you can observe on the fossil.

This picture shows a fossil of an ancient animal called Glyphithyreus. Glyphithyreus fossils have been found in rocks that are more than 30,000,000 years old.

closed choice

grade6

natural science

earth-science

Fossils

Compare fossils to modern organisms

The way an organism looks or acts is called a trait. Scientists use fossils to learn more about the traits of ancient organisms. Fossils can preserve the remains of body parts and activities. A fossil of a body part, such as a tail or a wing, can tell you what an organism looked like. A fossil of an organism's activities, such as a burrow or a footprint, can tell you about the organism's behavior. Here are three examples of fossils and the traits that you can observe from them: This is a fossil of an animal. This fossil tells you that the animal had a spiral-shaped shell. This is a fossil of a plant. This fossil tells you that the plant had small leaves arranged in a branched pattern. This is a fossil of an animal's footprint. This fossil tells you that the animal could walk on land. An organism's fossil may not show all of the organism's traits. This is because most body parts are destroyed during fossil formation. When an organism's body turns into a fossil, only a few body parts are usually preserved.

What is the source of the allusion in the sentence below? Warren described the situation he was facing with his boss as a catch-22.

closed choice

grade9

language science

figurative-language

Literary devices

Recall the source of an allusion

An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. "I'd better get home before I turn into a pumpkin!" Lila remarked. Here, Lila alludes to the fairy tale "Cinderella," in which Cinderella must leave the ball before the coach that brought her transforms into a pumpkin. The allusion shows that Lila must depart immediately.

The source of the allusion catch-22 is literature. Joseph Heller coined the term "catch-22" in his 1961 novel of the same name. In the novel, if an army pilot wants to avoid dangerous missions, he must be deemed mentally unfit; however, his desire to stay safe proves his sanity, so he can never be excused from a mission. Heller called this sort of predicament or dilemma a catch-22. The allusion catch-22 means a no-win situation.

Which of these organisms contains matter that was once part of the bilberry?

Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada. A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

closed choice

grade5

natural science

biology

Ecosystems

Interpret food webs II

A food web is a model. A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food. Arrows show how matter moves. A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating. An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web. An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows that starts from the bilberry. There are two arrows pointing to the collared lemming. One arrow starts from the bear sedge, and the other arrow starts from the lichen. Neither the bear sedge nor the lichen has an arrow pointing to it. So, in this food web, matter does not move from the bilberry to the collared lemming.

Complete the sentence. Saliva breaking down a piece of bread is a ().

closed choice

grade6

natural science

chemistry

Chemical reactions

Compare physical and chemical changes

Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.

Saliva breaking down a piece of bread is a chemical change. Bread is made up mostly of a chemical called starch. Saliva breaks the bonds between atoms in the starch molecules. The atoms then link together to form smaller, simpler molecules of sugar. The sugar is a different type of matter than the starch.

What is the capital of Maine?

closed choice

grade3

social science

geography

State capitals

Identify state capitals of the Northeast

Augusta is the capital of Maine.

Is Fromia monilis made up of one cell?

This organism is Fromia monilis. It is a member of the animal kingdom. Fromia monilis is commonly called a tile sea star. Did you notice that this tile sea star is missing one of its arms? If a tile sea star loses an arm, it can regrow the arm over time. This ability is called regeneration.

yes or no

grade4

natural science

biology

Classification

Describe, classify, and compare kingdoms

In the past, scientists classified living organisms into two groups: plants and animals. Over the past 300 years, scientists have discovered many more types of organisms. Today, many scientists classify organisms into six broad groups, called kingdoms. Organisms in each kingdom have specific traits. The table below shows some traits used to describe each kingdom. | Bacteria | Archaea | Protists | Fungi | Animals | Plants How many cells do they have? | one | one | one or many | one or many | many | many Do their cells have a nucleus? | no | no | yes | yes | yes | yes Can their cells make food? | some species can | some species can | some species can | no | no | yes

Fromia monilis is an animal. Animals are made up of many cells.

Which of these oceans does the prime meridian intersect?

closed choice

grade4

social science

geography

Maps

Use lines of latitude and longitude

Lines of latitude and lines of longitude are imaginary lines drawn on some globes and maps. They can help you find places on globes and maps. Lines of latitude show how far north or south a place is. We use units called degrees to describe how far a place is from the equator. The equator is the line located at 0° latitude. We start counting degrees from there. Lines north of the equator are labeled N for north. Lines south of the equator are labeled S for south. Lines of latitude are also called parallels because each line is parallel to the equator. Lines of longitude are also called meridians. They show how far east or west a place is. We use degrees to help describe how far a place is from the prime meridian. The prime meridian is the line located at 0° longitude. Lines west of the prime meridian are labeled W. Lines east of the prime meridian are labeled E. Meridians meet at the north and south poles. The equator goes all the way around the earth, but the prime meridian is different. It only goes from the North Pole to the South Pole on one side of the earth. On the opposite side of the globe is another special meridian. It is labeled both 180°E and 180°W. Together, lines of latitude and lines of longitude form a grid. You can use this grid to find the exact location of a place.

The prime meridian is the line at 0° longitude. It intersects the Arctic Ocean. It does not intersect the Indian Ocean or the Pacific Ocean.

Identify the question that Vicky's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Vicky planted 20 radish plants in a greenhouse, putting each plant in its own pot. She placed ten of the pots under bright light and the other ten pots under dim light. Vicky watered all the plants twice a day. After two months, she pulled the radish plants from the ground, threw away the leafy green tops, and measured the sizes of the radishes. She compared the sizes of the radishes grown under bright light to the sizes of the radishes grown under dim light. Figure: a radish plant in soil.

closed choice

grade8

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

Which i in column 4?

closed choice

grade3

social science

geography

Geography

Use a letter-number grid

A grid is made up of lines of squares. They are organized in rows and columns. A grid can help you use a map. A row is a line of squares that goes from side to side. Rows are marked with letters. A column is a line of squares that goes up and down. Columns are marked with numbers.

The gas station is in column 4.

What does the metaphor in this text suggest? Kiara felt a roller coaster of emotions when she heard the news.

closed choice

grade12

language science

figurative-language

Literary devices

Interpret the figure of speech

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. A metaphor compares two things that are not actually alike without using like or as. The snow formed a blanket over the town.

The text uses a metaphor, comparing two things that are not actually alike without using like or as. The metaphor Kiara felt a roller coaster of emotions suggests that Kiara had varied feelings. A roller coaster has a dramatic mix of ups and downs, and so do Kiara's feelings.

Is the following trait inherited or acquired? Emmy knows how to type.

Hint: Typing takes practice.

closed choice

grade4

natural science

biology

Traits and heredity

Identify inherited and acquired traits

Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.

People are not born knowing how to type. Instead, many people learn how to type. So, typing is an acquired trait.

Does this passage describe the weather or the climate?

Figure: Chad. Chad is a country in northern Africa. A high temperature of 43°C was recorded there last summer. Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.

closed choice

grade4

natural science

earth-science

Weather and climate

Weather and climate around the world

The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.

Read the passage carefully. Chad is a country in northern Africa. A high temperature of 43°C was recorded there last summer. The underlined part of the passage tells you about the high temperature in Chad last summer. This passage describes the atmosphere at a certain place and time. So, this passage describes the weather.

Is a paper clip a solid, a liquid, or a gas?

closed choice

grade3

natural science

physics

States of matter

Classify matter as solid, liquid, or gas

Solid, liquid, and gas are states of matter. Matter is anything that takes up space. Matter can come in different states, or forms. When matter is a solid, it has a definite volume and a definite shape. So, a solid has a size and shape of its own. Some solids can be easily folded, bent, or broken. A piece of paper is a solid. Also, some solids are very small. A grain of sand is a solid. When matter is a liquid, it has a definite volume but not a definite shape. So, a liquid has a size of its own, but it does not have a shape of its own. Think about pouring juice from a bottle into a cup. The juice still takes up the same amount of space, but it takes the shape of the bottle. Some liquids do not pour as easily as others. Honey and milk are both liquids. But pouring honey takes more time than pouring milk. When matter is a gas, it does not have a definite volume or a definite shape. A gas expands, or gets bigger, until it completely fills a space. A gas can also get smaller if it is squeezed into a smaller space. Many gases are invisible. Air is a gas.

A paper clip is a solid. You can easily bend a paper clip. But it will still have a size and shape of its own.

Based on this information, what is this rose plant's genotype for the flower color gene?

In a group of rose plants, some individuals have light yellow flowers and others have dark yellow flowers. In this group, the gene for the flower color trait has two alleles. The allele F is for light yellow flowers, and the allele f is for dark yellow flowers. A certain rose plant from this group has light yellow flowers. This plant has two alleles for light yellow flowers.

closed choice

grade8

natural science

biology

Genes to traits

Genetics vocabulary: genotype and phenotype

All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.

An organism's genotype for a gene is its combination of alleles for that gene. The rose plant has two alleles for light yellow flowers (F). So, the plant's genotype for the flower color gene is FF.

Select the organism in the same genus as the Eurasian beaver.

This organism is a Eurasian beaver. Its scientific name is Castor fiber.

closed choice

grade8

natural science

biology

Classification and scientific names

Use scientific names to classify organisms

Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.

A Eurasian beaver's scientific name is Castor fiber. The first word of its scientific name is Castor. This organism and the Eurasian beaver are in the same genus and the same species! Both organisms have the same scientific name, Castor fiber. Hystrix cristata is in the genus Hystrix. The first word of its scientific name is Hystrix. So, Hystrix cristata and Castor fiber are not in the same genus. Macropus agilis is in the genus Macropus. The first word of its scientific name is Macropus. So, Macropus agilis and Castor fiber are not in the same genus.

Is the following statement true or false? A plant cell has a cell wall.

true-or false

grade4

natural science

biology

Cells

Cell part functions: true or false

A plant cell has a cell wall. This statement is true. Not every cell has a cell wall, but a plant cell has one. The cell wall gives a plant cell its fixed shape.

What is the probability that a pea plant produced by this cross will have a tall stem?

In a group of pea plants, some individuals have a tall stem and others have a short stem. In this group, the gene for the stem height trait has two alleles. The allele for a short stem (h) is recessive to the allele for a tall stem (H). This Punnett square shows a cross between two pea plants.

closed choice

grade8

natural science

biology

Genes to traits

Use Punnett squares to calculate probabilities of offspring types

Offspring phenotypes: dominant or recessive? How do you determine an organism's phenotype for a trait? Look at the combination of alleles in the organism's genotype for the gene that affects that trait. Some alleles have types called dominant and recessive. These two types can cause different versions of the trait to appear as the organism's phenotype. If an organism's genotype has at least one dominant allele for a gene, the organism's phenotype will be the dominant allele's version of the gene's trait. If an organism's genotype has only recessive alleles for a gene, the organism's phenotype will be the recessive allele's version of the gene's trait. In a Punnett square, each box represents a different outcome, or result. Each of the four outcomes is equally likely to happen. Each box represents one way the parents' alleles can combine to form an offspring's genotype. Because there are four boxes in the Punnett square, there are four possible outcomes. An event is a set of one or more outcomes. The probability of an event is a measure of how likely the event is to happen. This probability is a number between 0 and 1, and it can be written as a fraction: probability of an event = number of ways the event can happen / number of equally likely outcomes You can use a Punnett square to calculate the probability that a cross will produce certain offspring. For example, the Punnett square below has two boxes with the genotype Ff. It has one box with the genotype FF and one box with the genotype ff. This means there are two ways the parents' alleles can combine to form Ff. There is one way they can combine to form FF and one way they can combine to form ff. | F | f F | FF | Ff f | Ff | ff Consider an event in which this cross produces an offspring with the genotype ff. The probability of this event is given by the following fraction: number of ways the event can happen / number of equally likely outcomes = number of boxes with the genotype ff / total number of boxes = 1 / 4.

What is the mass of a vacuum cleaner?

Select the best estimate.

closed choice

grade5

natural science

units-and-measurement

Units and measurement

Choose customary units of mass

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Mass is a measurement of how much matter something contains. There are many different units of mass. When you are using customary units, mass may be written with units of ounces, pounds, or tons. There are 16 ounces in 1 pound and 2,000 pounds in 1 ton. So, 1 ounce is less than 1 pound and much less than 1 ton. A slice of bread has a mass of about 1 ounce, while a can of beans has a mass of about 1 pound. A small car has a mass of about 1 ton.

The best estimate for the mass of a vacuum cleaner is 20 pounds. 20 ounces is too light and 20 tons is too heavy.

Is the following statement true or false? Plant cells do not have mitochondria.

true-or false

grade4

natural science

biology

Cells

Cell part functions: true or false

Plant cells do not have mitochondria. This statement is false. Not all cells have mitochondria, but most plant and animal cells have them.

Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?

The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.

closed choice

grade8

natural science

physics

Particle motion and energy

Identify how particle motion affects temperature and pressure

The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.

Each particle in the two samples has the same mass, and the particles in both samples have the same average speed. So, the particles in both samples have the same average kinetic energy. Because the particles in both samples have the same average kinetic energy, the samples must have the same temperature.

Is the following statement about our solar system true or false? The volume of Neptune is less than 75% of the volume of Uranus.

Use the data to answer the question below.

true-or false

grade6

natural science

earth-science

Astronomy

Analyze data to compare properties of planets

A planet's volume tells you the size of the planet. The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.

To determine if this statement is true, calculate the value of 75% of the volume of Uranus by multiplying its volume by 0.75. Then compare the result to the volume of Neptune. The volume of Neptune is 62,530 billion km^3, which is more than 51,248 billion km^3. So, the volume of Neptune is more than 75% of the volume of Uranus.

Which change best matches the sentence? A glacier carries small rocks and boulders as it moves down a mountain.

closed choice

grade3

natural science

earth-science

Earth events

Classify changes to Earth's surface II

Which figure of speech is used in this text? Amy's Bistro used to be a great place to go for a delicious and carefully prepared dinner, but nobody goes there anymore: it's too crowded.

closed choice

grade11

language science

figurative-language

Literary devices

Classify the figure of speech: euphemism, hyperbole, oxymoron, paradox

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic. The head of Human Resources would never refer to firing people, only to laying them off. Hyperbole is an obvious exaggeration that is not meant to be taken literally. I ate so much that I think I might explode! An oxymoron is a joining of two seemingly contradictory terms. Some reviewers are calling this book a new classic. A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth. Always expect the unexpected.

The text uses a paradox, a statement that might at first appear to be contradictory, but that may in fact contain some truth. Nobody goes there anymore: it's too crowded at first appears to be contradictory, because if no one goes to the restaurant, then the restaurant should be empty, not crowded. However, it contains some truth: if a restaurant is frequently perceived to be too crowded, many people will no longer want to go there.

Which figure of speech is used in this text? "This box weighs a ton!" Martin panted. "Carly, would you mind helping me carry it up the stairs?"

closed choice

grade11

language science

figurative-language

Literary devices

Classify the figure of speech: review

Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Anaphora is the repetition of the same word or words at the beginning of several phrases or clauses. We are united. We are powerful. We are winners. Antithesis involves contrasting opposing ideas within a parallel grammatical structure. I want to help, not to hurt. Apostrophe is a direct address to an absent person or a nonhuman entity. Oh, little bird, what makes you sing so beautifully? Assonance is the repetition of a vowel sound in a series of nearby words. Try to light the fire. Chiasmus is an expression in which the second half parallels the first but reverses the order of words. Never let a fool kiss you or a kiss fool you. A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic. The head of Human Resources would never refer to firing people, only to laying them off. Hyperbole is an obvious exaggeration that is not meant to be taken literally. I ate so much that I think I might explode! An oxymoron is a joining of two seemingly contradictory terms. Some reviewers are calling this book a new classic. A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth. Always expect the unexpected. Understatement involves deliberately representing something as less serious or important than it really is. As you know, it can get a little cold in the Antarctic.

The text uses hyperbole, an obvious exaggeration that is not meant to be taken literally. A ton is an exaggeration, since it would be impossible for one or two people to carry a box that weighed a ton, or 2000 pounds.

Complete the sentence. Burning a candle is a ().

closed choice

grade5

natural science

chemistry

Physical and chemical change

Compare physical and chemical changes

Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.

Burning a candle is a chemical change. Both the wick and the melted wax burn. They react with oxygen in the air and turn into soot, carbon dioxide, and water.

Think about the magnetic force between the magnets in each pair. Which of the following statements is true?

The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.

closed choice

grade4

natural science

physics

Magnets

Compare strengths of magnetic forces

Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other.

Distance affects the strength of the magnetic force. But the distance between the magnets in Pair 1 and in Pair 2 is the same. So, the strength of the magnetic force is the same in both pairs.

What is the name of the colony shown?

closed choice

grade7

social science

us-history

Colonial America

Identify the Thirteen Colonies

The colony is South Carolina.

What is the name of the colony shown?

closed choice

grade7

social science

us-history

Colonial America

Identify the Thirteen Colonies

The colony is Rhode Island.

What is the source of the allusion in the sentence below? Will's research on nineteenth-century philosophers led him down the rabbit hole.

closed choice

grade10

language science

figurative-language

Literary devices

Recall the source of an allusion

An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. "I'd better get home before I turn into a pumpkin!" Lila remarked. Here, Lila alludes to the fairy tale "Cinderella," in which Cinderella must leave the ball before the coach that brought her transforms into a pumpkin. The allusion shows that Lila must depart immediately.

The source of the allusion down the rabbit hole is literature. Lewis Carroll's Alice's Adventures in Wonderland tells the story of a young girl who follows a white rabbit down a rabbit hole and finds herself in a series of adventures in a surreal world. The allusion down the rabbit hole means on a strange or difficult exploration.

Which country is highlighted?

closed choice

grade6

social science

geography

Oceania: geography

Identify and select countries of Oceania

This country is Solomon Islands.

In this food web, which organism contains matter that eventually moves to the bolete fungus?

Below is a food web from Shenandoah National Park, a forest ecosystem in Virginia. A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

closed choice

grade8

natural science

biology

Ecological interactions

Interpret food webs II

A food web is a model. A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food. Arrows show how matter moves. A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating. An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web. An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows to the bolete fungus.There are five paths matter can take from the swallowtail caterpillar to the bolete fungus: swallowtail caterpillar->gray fox->bolete fungus. swallowtail caterpillar->gray fox->bobcat->bolete fungus. swallowtail caterpillar->pine vole->gray fox->bolete fungus. swallowtail caterpillar->pine vole->gray fox->bobcat->bolete fungus. swallowtail caterpillar->pine vole->black racer->bolete fungus. parasol fungus. No arrows point from the parasol fungus to any other organisms. So, in this food web, matter does not move from the parasol fungus to the bolete fungus.. There is one path matter can take from the silver maple to the bolete fungus: silver maple->beaver->bobcat->bolete fungus. black bear. The only arrow pointing from the black bear leads to the parasol fungus. No arrows point from the parasol fungus to any other organisms. So, in this food web, matter does not move from the black bear to the bolete fungus.. There are eight paths matter can take from the persimmon tree to the bolete fungus: persimmon tree->swallowtail caterpillar->gray fox->bolete fungus. persimmon tree->swallowtail caterpillar->gray fox->bobcat->bolete fungus. persimmon tree->swallowtail caterpillar->pine vole->gray fox->bolete fungus. persimmon tree->swallowtail caterpillar->pine vole->gray fox->bobcat->bolete fungus. persimmon tree->swallowtail caterpillar->pine vole->black racer->bolete fungus. persimmon tree->pine vole->gray fox->bolete fungus. persimmon tree->pine vole->gray fox->bobcat->bolete fungus. persimmon tree->pine vole->black racer->bolete fungus.

What kind of sentence is this? How many articles did Oliver write before his publisher offered him a book contract?

closed choice

grade6

language science

punctuation

Sentences, fragments, and run-ons

Is the sentence declarative, interrogative, imperative, or exclamatory?

There are four kinds of sentences. A declarative sentence is a statement, and it always ends with a period. The nurse told Mr. Abrams to roll up his sleeve so that she could check his blood pressure. An interrogative sentence is a question, and it always ends with a question mark. Do you have any plans for the upcoming weekend? An imperative sentence is a command. It makes a request or tells someone to do something, and it usually ends with a period. If the command shows strong feeling, it ends with an exclamation point. For this assignment, use references to support your claims. Don't drive so quickly in the construction zone! An exclamatory sentence is like a statement, but it shows surprise or strong feeling. An exclamatory sentence always ends with an exclamation point. I can't wait to travel through Europe this summer!

The sentence asks something, and it ends with a question mark. It is an interrogative sentence.

Select the plant.

closed choice

grade2

natural science

biology

Classification

Identify plants and animals

Plants and animals are living things. Living things are called organisms. Plants come in many shapes and sizes. Most plants grow in the ground. They might grow leaves, flowers, and fruit. Plants cannot move around on their own like animals can. Animals also come in many shapes and sizes. Most animals can move around. Animals might run, swim, jump, or fly. Animals eat plants or other organisms for food.

A bumble bee is an animal. It drinks nectar from flowers. A bumble bee is an insect. Bumble bees have soft hairs that make them look fuzzy. A pumpkin vine is a plant. It has large flat leaves. The largest pumpkins can be as big as a car!

Look at the picture. Which word best describes the sound this clock makes?

closed choice

grade2

language science

writing-strategies

Descriptive details

Choose the sensory details that match the picture

When you write, you can use sensory details. These sense words help your reader understand what something looks, sounds, tastes, smells, or feels like. Sensory Category | Description Sight | These are words like bright, clean, and purple. A reader can imagine looking at these details. Sound | These are words like hissing, buzzing, and ringing. A reader can imagine hearing these details. Taste | These are words like juicy, sweet, and burnt. A reader can imagine tasting these details. Smell | These are words like fruity, sweet, and stinky. A reader can imagine smelling these details. Touch | These are words like fuzzy, wet, and soft. A reader can imagine feeling these details. Many sense words can describe more than one sense. For example, soft can describe a touch or a sound. And sweet can describe a taste or a smell.

Look at the picture. The word ringing describes the sound this clock makes. You can tell by looking at the girl covering her ears. Purring and splashing can also describe sounds. But they do not describe the sounds this clock makes.

What is the mass of a small candy bar?

Select the best estimate.

closed choice

grade4

natural science

units-and-measurement

Units and measurement

Choose customary units of mass

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Mass is a measurement of how much matter something contains. There are many different units of mass. When you are using customary units, mass may be written with units of ounces, pounds, or tons. There are 16 ounces in 1 pound and 2,000 pounds in 1 ton. So, 1 ounce is less than 1 pound and much less than 1 ton. A slice of bread has a mass of about 1 ounce, while a can of beans has a mass of about 1 pound. A small car has a mass of about 1 ton.

The best estimate for the mass of a small candy bar is 1 ounce. 1 pound and 1 ton are both too heavy.

The trucks begin to move at the same speed. Which truck needs a larger force to start moving?

Two mail trucks are loaded with mail. The trucks are the same. But they are carrying different amounts of mail.

closed choice

grade2

natural science

physics

Force and motion

How do mass and force affect motion?

A force is a push or a pull. A force can make an object start moving or stop an object that is moving. A force can also make an object speed up, slow down, or change direction. Forces can be different sizes. Think about trying to move a heavy object and a light object. Imagine you want to move them at the same speed. You will need to use a larger force to move the heavy object.

Look for the mail truck that is heavier. A mail truck carrying 500 pounds of mail is heavier than a mail truck carrying 350 pounds of mail. So, the mail truck carrying 500 pounds needs a larger force to start moving at the same speed as the other mail truck.

Which sentence uses a simile?

closed choice

grade4

language science

figurative-language

Literary devices

Identify similes and metaphors

Similes and metaphors are figures of speech that compare two things that are not actually alike. A simile compares two things by saying that one is like the other. Similes often use the words like and as. My sister runs like a cheetah. The sister's running and a cheetah's running are compared using the word like. A cheetah is known for running fast, so the simile means that the sister also runs fast. The cat's fur was as dark as the night. The cat's fur and the night are compared using the word as. The night is dark, so the simile means that the cat's fur is also dark. A metaphor compares two things by saying that one of them is the other. Unlike similes, metaphors don't use the word like or as. The snow formed a blanket over the town. The snow and a blanket are compared without the word like or as. A blanket is a large piece of cloth that completely covers a bed. The metaphor makes the reader imagine that the snow becomes a blanket, covering the town completely. Using similes and metaphors in your writing can help you create an interesting picture for the reader.

This sentence uses a simile: Mr. Dotson's legs were as long as sunflower stalks. The words legs and sunflower stalks are compared using the word as. This sentence uses a metaphor: Mr. Dotson's long legs were sunflower stalks. The words legs and sunflower stalks are compared without the word like or as.

Which animal's skin is better adapted as a warning sign to ward off predators?

Opalescent nudibranchs have stinging cells in their brightly colored skin. The bright colors serve as a warning sign that the animal is toxic and dangerous. The 's skin is adapted to ward off predators. Figure: opalescent nudibranch.

closed choice

grade4

natural science

biology

Adaptations

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Look at the picture of the opalescent nudibranch. The opalescent nudibranch has stinging cells in its brightly colored skin. Its skin is adapted to ward off predators. The bright colors serve as a warning sign that the opalescent nudibranch is toxic and dangerous. Now look at each animal. Figure out which animal has a similar adaptation. The sharpnose-puffer has a poisonous body with brightly colored skin. Its skin is adapted to ward off predators. The lechwe has light-brown fur covering its skin. Its skin is not adapted to be a warning sign that wards off predators.

In this food chain, the midge larva is a consumer. Why?

This diagram shows a food chain from the River Frome, a freshwater ecosystem in England.

closed choice

grade4

natural science

biology

Ecosystems

Identify roles in food chains

Every organism needs food to stay alive. Organisms get their food in different ways. A food chain shows how organisms in an ecosystem get their food. Producers make their own food. Many producers use carbon dioxide, water, and sunlight to make sugar. This sugar is food for the producer. Consumers eat other organisms. Consumers cannot make their own food.

In this food chain, the midge larva is a consumer because it eats another organism. The midge larva in this food chain eats the diatom.

Select the vertebrate.

Hint: Mammals, birds, fish, reptiles, and amphibians are vertebrates.

closed choice

grade3

natural science

biology

Classification

Identify vertebrates and invertebrates

Vertebrates and invertebrates are both groups of animals. A vertebrate has a backbone. The backbone is made of many bones in an animal's back. A vertebrate's backbone helps connect the different parts of its body. In the drawings below, each vertebrate's backbone is colored orange. An invertebrate does not have a backbone. In fact, invertebrates do not have any bones! Some invertebrates have a hard outer cover on their body. Other invertebrates have a soft body.

A saturn butterfly is an insect. Like other insects, a saturn butterfly is an invertebrate. It does not have a backbone. It has a hard outer cover. A giraffe is a mammal. Like other mammals, a giraffe is a vertebrate. It has a backbone.

Which logical fallacy is used in the text? Did you really vote for Samir as class treasurer? Didn't you hear that his uncle was imprisoned for embezzling $1.5 million?

closed choice

grade6

language science

writing-strategies

Developing and supporting arguments

Classify logical fallacies

A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions. A logical fallacy may present irrelevant information: Fallacy | Description ad hominem | a personal attack meant to discredit one's opponent appeal to nature | an argument that assumes the natural choice is always the best choice bandwagon fallacy | an argument that assumes the popular choice is always the best choice circular reasoning | an argument that supports a claim with the claim itself guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something red herring | the use of a completely unrelated topic in support of a claim A logical fallacy may misrepresent the issues at hand: Fallacy | Description false causation | the assumption that because two things happened together, one caused the other false dichotomy | an argument that presents only two choices when more options exist hasty generalization | a very broad claim based on very little evidence straw man | a misrepresentation of an opponent's position that makes it easier to argue against

The text argues that Samir can't be trusted with money, because his uncle embezzled money. However, even though his uncle couldn't be trusted with money, that doesn't necessarily mean that Samir can't be trusted with it. This illustrates a type of logical fallacy known as guilt by association.

Which is this organism's scientific name?

This organism is Cassiopea andromeda. It is also called an upside-down jellyfish.

closed choice

grade7

natural science

biology

Classification and scientific names

Identify common and scientific names

An organism's common name is the name that people normally call the organism. Common names often contain words you know. An organism's scientific name is the name scientists use to identify the organism. Scientific names often contain words that are not used in everyday English. Scientific names are written in italics, but common names are usually not. The first word of the scientific name is capitalized, and the second word is not. For example, the common name of the animal below is giant panda. Its scientific name is Ailuropoda melanoleuca.

Cassiopea andromeda is written in italics. The first word is capitalized, and the second word is not. So, Cassiopea andromeda is the scientific name.

What is the capital of Oklahoma?

closed choice

grade4

social science

geography

State capitals

Identify state capitals of the Southeast

Oklahoma City is the capital of Oklahoma.

How long is a soccer field?

Select the best estimate.

closed choice

grade4

natural science

units-and-measurement

Units and measurement

Choose metric units of distance

Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. When you are using metric units, length can be written with units of millimeters, centimeters, meters, or kilometers. One meter contains 100 centimeters or 1,000 millimeters. So, 1 meter is larger than 1 centimeter, and 1 centimeter is larger than 1 millimeter. The tip of the pencil shown here is only 1 millimeter wide, but the pencil is about 16 centimeters long. A red fox is about 1 meter long. The Sydney Harbour Bridge in Australia is about 1,000 meters, or 1 kilometer, in length.

The best estimate for the length of a soccer field is 105 meters. 105 centimeters is too short and 105 kilometers is too long.

Which tense does the sentence use? Ben carefully spelled the word aloud.

closed choice

grade5

language science

verbs

Verb tense

Is the sentence in the past, present, or future tense?

Present tense verbs tell you about something that is happening now. Most present-tense verbs are regular. They have no ending, or they end in -s or -es. Two verbs are irregular in the present tense, to be and to have. You must remember their forms. Past tense verbs tell you about something that has already happened. Most past-tense verbs are regular. They end in -ed. Some verbs are irregular in the past tense. You must remember their past-tense forms. Future tense verbs tell you about something that is going to happen. All future-tense verbs use the word will. Present | Past | Future walk, walks | walked | will walk go, goes | went | will go

The sentence is in past tense. You can tell because it uses a past-tense verb, spelled. The verb ends in -ed and tells you about something that has already happened.

Which property matches this object?

Select the better answer.

closed choice

grade2

natural science

physics

Materials

Identify properties of an object

An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.

Look at the object. Think about each property. A slippery object is hard to hold onto or stand on. The wet paint is slippery. A scratchy object is rough and itchy against your skin. The wet paint is not scratchy.

Which country is highlighted?

closed choice

grade7

social science

geography

The Americas: geography

Identify and select countries of the Caribbean

This country is Dominica.

Which animal's skin is better adapted as a warning sign to ward off predators?

Fire salamanders have poisonous glands in their brightly colored skin. The bright colors serve as a warning sign that the animal is poisonous. The 's skin is adapted to ward off predators. Figure: fire salamander.

closed choice

grade3

natural science

biology

Adaptations

Animal adaptations: skins and body coverings

An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.

Look at the picture of the fire salamander. The fire salamander has a poisonous body with brightly colored skin. Its skin is adapted to ward off predators. The bright colors serve as a warning sign that the fire salamander is poisonous. Now look at each animal. Figure out which animal has a similar adaptation. The Spanish shawl nudibranch has stinging cells in its brightly colored skin. Its skin is adapted to ward off predators. The impala has yellow-brown fur. Its skin is not adapted to be a warning sign that wards off predators.

Identify the question that Donald's experiment can best answer.

The passage below describes an experiment. Read the passage and then follow the instructions below. Donald set up five pairs of platform bird feeders around his yard. He filled one feeder in each pair with sunflower seeds and the other feeder with flax seeds. For one week, Donald watched cardinals visiting the feeders during the same hour each morning. During his observations, Donald counted the number of visits by cardinals to feeders with sunflower seeds and the number of visits by cardinals to feeders with flax seeds. Figure: a cardinal visiting a platform feeder with sunflower seeds.

closed choice

grade7

natural science

science-and-engineering-practices

Designing experiments

Identify the experimental question

Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?

What do these two changes have in common? burning a marshmallow over a campfire boiling an egg

closed choice

grade7

natural science

chemistry

Chemical reactions

Compare physical and chemical changes

Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.

Step 1: Think about each change. Burning a marshmallow is a chemical change. The heat from the fire causes the type of matter in the marshmallow to change. The marshmallow becomes black and crispy. Boiling an egg is a chemical change. The heat causes the matter in the egg to change. Cooked eggs and raw eggs are made of different types of matter. Step 2: Look at each answer choice. Both are only physical changes. Both changes are chemical changes. They are not physical changes. Both are chemical changes. Both changes are chemical changes. The type of matter before and after each change is different. Both are caused by heating. Both changes are caused by heating. Both are caused by cooling. Neither change is caused by cooling.