| A | B |
|---|
| Amphibian | a vertebrate that usually lives in water in the early part of its life: it breathes with gills and then later develops lungs |
| Bird | a vertebrate that has wings, is covered with feathers, and hatches from a hard-shelled egg |
| Fish | a vertebrate that lives in water and has gills for breathing and fins for swimming |
| Gill | a feathery structure on each side of a fish’s head that lets the fish breathe underwater |
| Insects | usually small arthropod invertebrate that have an adult stage characterized by three pairs of legs and a body segmented into head, thorax, and abdomen and usually having two pairs of wings |
| Invertebrate | an animal that does not have a backbone |
| Mammal | a vertebrate, such as a cat that has hair or fur and that feeds it young with milk |
| Reptile | a vertebrate, such as a lizard, that has dry scaly skin and lays eggs that have a leathery shell |
| Vertebrate | an animal that has a backbone |
| Habitat | where an animal lives, its environment |
| hibernation | when an animal sleeps or is dormant during the cold months |
| estivation | when an animal sleeps or is dormant during the warm months |
| migration | movement of a group of animals from one place to another due to changing seasons |
| camouflage | how an animal's body covering blends in with its environment to hide it from predators |
| metamorphosis | when an animal changes form |
| cold-blooded | body temperature changes with the weather |
| warm-blooded | body temperature remains constant |
