coyotes: a small wild animal like a dog that lives in North America.

Amphibian: an animal, such as a frog, that lives both on land and in water but must produce its eggs in water.

Worm: a small animal with a long, narrow, soft body without arms, legs, or bones.

Prehistoric Times: In this sense, prehistory covers the period of time that extends from the appearance of the first hominids, ancestors of Homo Sapiens, to the production of the first written documents, dating from the year 3,300 a. of C

chemical: any basic substance that is used in or produced by a reaction involving changes to atoms or molecules.

arthropod: a type of animal with no spine, a hard outer skin, legs with bones joined together, and a body divided into different parts, for example a spider, crab, or ant.

Mammal: any animal of which the female feeds her young on milk from her own body. Most mammals give birth to live young, not eggs.

earth: the planet third in order of distance from the sun, between Venus and Mars; the world on which we live.

asteroid: an object like a very large rock that goes around the sun like a planet.

Bacteria: very small organisms that are found everywhere and are the cause of many diseases.

Reptile: an animal that produces eggs and uses the heat of the sun to keep its blood warm.

Insect: a type of very small animal with six legs, a body divided into three parts and usually two pairs of wings, or, more generally, any similar very small animal.