| A | B |
|---|
| specialization | adaptation of a cell for a particular function |
| cell junction | connections between cells that hold the cells together as a unit |
| ingestion | animal takes in organic material |
| zygote | first cell of a new individual |
| neurons | cells of nervous tissue |
| radial symmetry | parts branched out from a central line |
| dorsal | top |
| ventral | bottom |
| anterior | head |
| posterior | tail |
| bilateral symmetry | two similar halves on either side of a central plane |
| cephalization | concentration of sensory and brain structures in the anterior end of an animal; a cephalized animal has a head |
| germ layers | fundamental tissue types found in the embryos of all animals exept sponges |
| notochord | firm, flexible rod of tissue located in the dorsal part of the body |
| dorsal nerve cord | hollow tube lying just above the notochord |
| pharyngeal pouches | small outpockets of anterior part of the digestive tract |
| postanal tail | muscle tissue and lies behind the posterior opening of the digestive tract |
| segmentation | series of similar repeating units |
| exoskeleton | rigide outer covering that protects th soft tissues of many animals, such as lobsters |
| hermaphrodite | an organism that produces both male and female gametes, allowing it to function as both male and female |
