| A | B |
|---|
| metamorphosis | change in body form some animals go through as they mature |
| invertebrate | an animal without a backbone |
| appendages | structures, like legs or antennae, that grow out from a body |
| cnidarians | hollow-bodied animal that has stinging cells |
| radial symmetry | type of symmetry in which body parts are arranged in a circle around a central point |
| exoskeleton | protective outer covering on arthropods |
| mollusk | soft-bodied invertebrate usually with a shell |
| closed-circulatory system | circulatory system in which blood is contained in vessels |
| polyp | vase-shaped body plan, like that of a hydra |
