| A | B |
|---|
| metamorphosis | Change of body form that can be complete or incomplete. |
| cnidarian | A radially symmetrical, hollow bodied animal with two cell layers organized into tissues |
| closed circulatory system | A type of blood circulation system in which blood is transported through blood vessels rather than washing over the organs. |
| mollusk | A soft bodied bilaterally symmetrical invertebrate with a large muscular foot, a mantle and an open circulatory system; usually has a shell. |
| open circulatory system | A type of blood circulation system that lacks blood vessels and in which blood washes over the organs. |
| symmetry | Arrangement of individual body parts can be radial, bilateral or asymmetrical. |
| exoskeleton | Rigid protective body covering of an arthropod that supports the body and reduces water loss. |
| gills | Organ that allows a water-dwelling animal to exchange carbon dioxide for dissolved oxygen in the water. |
| arthropod | Bilaterally symmetrical animal with jointed appendages, a protective exoskeleton and a segmented body. |
| invertebrate | An animal without a backbone. |
| mantle | Thin layer of tissue that covers a mollusks body and that can secrete a shell. |
| medusa | Free swimming bell shaped body form in the life cycle of a cnidarian. |
| polyp | Vase shaped usually sessile body form in the life cycle of a cnidarian. |
| appendage | Structure such as a claw, leg or antennae that grows from the body. |
| radula | A scratchy tongue like organ in many mollusks that has rows of teethlike projection used to scrape and grate food. |
