| A | B |
|---|
| zoology | study of animals |
| invertebrates | no backbone |
| vertebrates | animals with backbones |
| symmetry | means body can be cut into two equal halves |
| posterior | the tail end of the animal |
| anterior | the head end of the animal |
| dorsal | the top or upper side of the animal |
| ventral | the belly or lower side of the animal |
| pores | holes through which water flows |
| jelly fish | member of the Coelenterates |
| ectoderm | first germ layer |
| mesoderm | middle germ layer |
| endoderm | inner germ layer |
| flatworms | simplest animals to show bilateral symmetry |
