| A | B |
|---|
| vertebrate | an animal with a backbone |
| invertebrate | an animal not having a backbone |
| animal | a multicellular heterotroph whose cells lack cell walls |
| spicules | thin, spiny structure that forms skeleton of many sponges |
| sexual reproduction | reproduction requiring two parents |
| asexual reproduction | reproduction requiring only one parent |
| nematocysts | special stinging structure in a cnidarian |
| regeneration | ability to regrow lost body parts |
| parasite | organism that feeds on other living organisms |
| host | organism in which another organism lives |
