| A | B |
|---|
| backbone | the main bone, made up of many small bones joined together, that runs along the middle of the back on some animals |
| exoskeleton | a hard outer covering that supports and protects some animals without backbones |
| molt | to shed an animal's outer covering |
| gills | organs for breathing found in fish and amphibians |
| amphibian | one of a large group of animals with backbones that lie part of their lives in water and part on land |
| reptile | an animal with a backbone that has dry, scaly skin |
| mammal | an animal with a backbone that usually has hair on its body and feeds milk to its young |
| what two groups do scientists group animals? | with a backbone and without a backbone |
| Animals without backbones have many different ________, _________,and ___________. | sizes, shapes, and body parts |
| Insects and other animals with jointed legs have___________________ | different number of legs and body parts. |
| Fish and amphibians are animals that have backbones and___________ | spend all or part of their lives in water. |
| Reptiles are animals with backbones that have ___________ | dry, scaly skin and reproduce by laying eggs or giving birth to live young. |
| Birds are warm blooded animals that have backbones and___________ | feathers covering their bodies. |
| Mammals are animals with backbones that have hair and__________ | feed milk to their young. |
| Most mammals give birth to__________ | live young and care for their young. |
