| A | B |
|---|
| bilateral symmetry | a body plan in which two halves of an organism's body are mirror images of each other |
| invertebrate | an animal without a backbone |
| radial symmetry | a body plan in which the parts of the body are arranged in a circle around a central point |
| asymmetrical | without symmetry |
| ganglia | groups of nerve cells |
| gut | the pouch where food is digested in animals |
| coelom | a cavity in the body of some animals where the gut and organs are located |
| open circulatory system | a circulatory system consisting of a heart that pumps blood through spaces called sinuses |
| closed circulatory system | a circulatory system in which a heart circulates blood through a network of vessels that forms a closed loop |
| segment | one of many identical or almost identical repeating body parts |
| exoskeleton | an external skeleton make of protein and chitin; found on arthropods |
| compound eye | an eye that is made of many identical, light-sensitive cells that work together |
| antennae | feelers on an arthropods head that respond to touch, taste, or smell |
| mandible | a jaw found on some arthropods |
| metamorphosis | the process in which an insect or other animal changes form as it develops from an embryo or larva to an adult |
| endoskeleton | an internal skeleton |
| water vascular system | a system of water pumps and canals found in all echinoderms that allows them to move, eat, and breathe |
