| A | B |
|---|
| lamprey | jawless fish |
| skate | cartilaginous fish |
| trout | bony fish |
| bony fish | most fish belong to this class |
| cartilage | flexible tissue that is the skeleton in sharks |
| fins | fish move through water using these |
| endotherm | animal whose body temperature stays the same |
| ectotherm | animal whose body temperature changes with its environment |
| endoskeleton | vertebrate, skull, and internal skeleton |
| chordates | at some time have a notochord, gill slits, and hollow nerve cord |
| notochord | flexible rod that extends along the length of an organism |
| incisors | teeth that bite and cut |
| down feathers | soft, fluffy feathers that insulate bird's skin |
| mammary glands | produce milk that female mammals feed their young |
| carnivores | animals that eat other animals |
| barbs | branches of the feather's main shaft |
| molars | teeth that grind and crush |
| omnivores | animals that eat both plants and animals |
| mammals | endothermic vertebrates that produce milk |
| herbivores | animals that eat plants |
| placenta | organ developed by growing embryo |
