| A | B |
|---|
| radial symmetry | body parts extend from the center of the body |
| bilateral symmetry | body partys have mirror images on the left and right side |
| cephalization | the concentration of sense organs and nerve cells in the front of the body |
| coelom | a body cavity |
| intracellular digestion | food is broken down inside cells |
| extracellular digestion | food is broken down outside cells in a digestive tracts and then absorbed into the body |
| open circulatory system | blood is only partially contained within a system of blood vessels |
| closed circulatory system | a heart or heartlike organ forces blood through vessels that extend throughout the body |
| hydrostatic skeleton | muscles surround a fluid filled body cavity that supports the muscles |
| exoskeleton | a hard body covering made of chitin |
| endoskeleton | a structural support located inside the body |
| external fertilization | eggs are fertilized outside the female's body |
| internal fertilization | eggs are fertilized inside the female's body |
