| A | B |
|---|
| invertebrates | animals without backbone |
| ganglion | a concentrated mass of nerve cells |
| coelem | body cavity that surrounds the gut |
| gut | a pouch where food is digested |
| bilateral symmetry | 2 sides of body mirror each other (ant) |
| radial symmetry | body is organized around a center (starfish) |
| asymmetrical | body has no lines of symmetry (sponges) |
| pores | allows water to flow into sponge |
| spicules | make up a sponge's skeleton |
| osculum | allows water to leave the sponge |
| collar cells | filter and digest foods for sponges |
