Fast heart rate: Tachycardia means fast heart beat. Sinus node is the structure where normally heart rhythm and beat is originated, and it naturally responds to stimuli when the heart needs to beat faster. Inappropriate sinus tachycardia is when the heart is beating fast, when it shouldn't. ...Read more.
An atom is the smallest unit of an element that retains the identity (and the chemical properties) of that element. + 66 others found this useful. Sandra Pinzon.Edit.he atom is the smallest particle of an element that retains it's characteristics. Sub-atomic particles such as protons, neutrons and electrons form the atom and it is the amo â¦ unt of each of these sub-atomic particles that make the element that element. 5 people found this useful.
The Building Blocks of Matter All matter, from a rock to an animal to the magma at the center of the Earth, is made from different combinations of 92 naturally occurring substances known as elements. The smallest quantity of an element that still exhibits the characteristics of that element is known as an atom. One atom of carbon, for example, is the smallest piece of matter that still retains the chemical and physical characteristics of carbon.