| A | B |
|---|
| vertebrates | animals with backbones |
| invertebrates | animals with no backbones |
| arthropods | invertegrates that have jointed legs and segmented bodies |
| chitin | the tough material that makes up the exoskeleton |
| spiracles | small openings in the insect's abdomen which allows air to enter |
| tracheae | breathing tubes similiar to lungs |
| antennae | long, movable structure on the head of insects used to feel, hear, and taste |
| arachnid | arthropods that have four pairs of legs and breathe by tracheae |
| head, thorax, and abdomen | three body regions of an insect |
| crustaceans | arthropods with hard crusty shells |
| regeneration | replacement of lost body parts |
| krill | small, crustaceans that is food for larger animals |
| barnacle | this crustacean may be a world traveler even though it stays in one place at all times |
| gastropod | "stomach-foot" |
| mollusks | miniature "musselmen" |
| protozoans | single-celled animals |
| book lung | thin sheets of tissue that help a spider to breathe |
| pseudopods | projections of an ameba's protoplasm |
| cilia | tiny threads on a paramecium |
| setae | sensitive hairs on a spider |
