Select the one animal that has all of the arachnid traits listed above.
Earthworms live in soil and have no limbs. Their bodies are soft, cylindrical, and made up of many segments. Castor bean ticks have a hard exoskeleton, eight legs, and no antennae. They feed on blood from mammals, including deer and people.
Arachnids are a group of animals with similar traits. The following traits can be used to identify arachnids:
They have eight legs.
They have an exoskeleton.
They have no antennae. Observe the animals and read the descriptions.
Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live.
How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group.
To decide if an animal is part of a group, look at the traits of the group.
Arachnids have the following traits:
They have eight legs.
They have an exoskeleton.
They have no antennae.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
A castor bean tick has the following traits:
It has eight legs.
It has an exoskeleton.
It has no antennae.
A castor bean tick has the traits of an arachnid. A castor bean tick is an arachnid.
An earthworm has the following traits:
It has a soft, cylindrical body.
It has no limbs.
It is made up of segments.
An earthworm does not have all of the traits of an arachnid. An earthworm is a segmented worm.