Invertebrates

3. biologist classify animals into about 35 different groups
5. is a tiny hole or opening that allows the passage of liquid
6. invertebrates with soft, unsegmented bodies that are often protected by a hard outer shell
8. structures or behaviors that allow animal to perform these basic functions in their environments
11. an organism that lives inside or on another organism
14. a process in which an animal’s body undergoes dramatic changes in form during its life cycle
15. most mollusks that live in water have organs that remove oxygen from the water
18. long,round body
19. some gastropods are herbivores, animals that only eat plants
20. invertebrate animals that usually have no body symmetry and never have tissues or organs

1. some species of cnidarians live in a colony, a group of many individual animals
2. is an appendage attached to the head that contains sense organs
4. the process of shedding an outgrown exoskeleton
7. most bivalves are omnivores, animals that eat plants and animals (both)
9. chemicals that kill pests
10. a larva is an immature form of an animal that looks very different from the adult
12. invertebrates with an internal skeleton and a system of fluid-filled tubes called a water vascular system
13. an animal that carries pollen among plants
16. Some are carnivores, that only eat other animals
17. long,they are flat and as soft as a jelly