| A | B |
|---|
| flagellum | whiplike structure on some cells |
| pores | tiny openings |
| spicules | small hard needlelike structures on a sponge |
| cnidocytes | stinging cells |
| medusa | umbrellalike form of a cnidarian |
| polyp | cuplike form of a cnidarian |
| tentacles | long, armlike structures |
| ectoderm | outer tissue layer |
| endoderm | inner tissue layer |
| mesoderm | middle tissue layer |
| closed circulatory system | an organ system in which blood moves through vessels |
| setae | tiny, hairlike bristles |
| 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 |
| abdomen | third section of an insect's body |
| spiracles | openings to air tubes of a grasshopper |
| thorax | middle section of an insect's body |
| tympanum | hearing organ in a grasshopper |
| cocoon | protective covering around the pupa |
| larva | wormlike stage of insect development |
| metamorphosis | changes during the stages of development of an insect |
| nymph | young insect that looks like the adult |
| pupa | resting stage during complete metamorphosis |
| echinoderms | spiny-skinned animals |
| endoskeleton | internal skeleton |
| tube feet | small suckerlike structures of echinoderms |
| regeneration | ability to regrow lost parts |
