| A | B |
| flagellum | whiplike structures on some cells |
| pores | tiny openings |
| spicules | small, hard needlelike structures of a sponge |
| cnidocytes | stinging cells |
| medusa | umbrellalike form of a cnidarian |
| polyp | cuplike form of a cnidarian |
| tentacles | long, armlike structures |
| mantle | thin, membrane that covers a mollusk's organs |
| radula | rough, tonguelike organ of a snail |
| chitin | hard material that makes up the exoskeleton of arthropods |
| exoskeleton | hard covering that supports and protects the body |
| molting | process by which an animal sheds its outer covering |