| A | B |
|---|
| Appendage | jointed structures of arthropods, such as legs, wings, or antennae |
| Closed circulatory system | blood circulation system in which blood moves through the body in closed vessels |
| Crop | digestive system sac in which earthworms store ingested soil |
| Exoskeleton | thick, hard, outer covering that protects and supports arthropod bodies and provides places for muscle to attach |
| Gill | organ that exchanges carbon dioxide for oxygen in water |
| Gizzard | muscular digestive system in which earthworms grind soil and organic matter |
| Mantle | thin layer of tissue that covers a mollusk’s body organs; secretes the shell or protects the body of mollusks without shells |
| Metamorphosis | process in which many insects species change their body form to become adults; can be complete (egg, larva, pupa, adult) or incomplete (egg, nymph, adult) |
| Molting | shedding and replacing of an arthropod’s exoskeleton |
| Open circulatory system | blood circulation system in which blood moves through vessels and into open spaces around the body |
| Radula | in gastropods, the tongue-like organ with rows of teeth used to scrape and tear food |
| Setae | bristle-like structures on the outside of each body segment that helps segmented worms move |
| Spiracle | openings in the abdomen and thorax of insects through which air enters and waste gases leave |
| Tube feet | hydraulic, hollow, thin-walled tubes that end in suction cups and enable echinoderms to move |
| Water vascular system | network of water-filled canals that allows echinoderms to move, captured food, give off wastes, and exchange carbon dioxide and oxygen |
