| A | B |
|---|
| Animals that do not have backbones are called | invertebrates |
| The front end of an organism is the | anterior |
| ____________ and archaeocytes are cells that digest food in sponges. | Choanocytes |
| Cnidarians have stinging tentacles around their | mouths |
| The life cycle of most cnidarians includes medusas and | polyps |
| The internal space of a cnidarian is called a (an) | gastrovascular cavity |
| Cnidarians have a (an) _________ that enables them to respond to touch by pulling their tentacles inside their bodies. | nerve net |
| Why are sponges classified as animals? | Sponges are multicellular and heterotrophic, have no cell walls, and contain a few specialized cells. |
| Where does extracellular digestion take place in cnidarians? | Extracellular digestion takes place in the gastrovascular cavity. |
| What are the characteristics of flatworms? | A flatworm is a soft, flattened worm that has tissues, organ system, three embryonic germ layers, bilateral symmetry, and cephalization |
