1. Fishes, Amphibians and Reptiles

2. Animals with a backbone are called vertebrates.

3. Animals that maintain a constant body temperature are called endotherms.

4. Animals whose body temperature fluctuates with the temperature of their environment are called _____. ecotherms

5. ____ are fanlike structures that help fish move, steer, stop, and balance. Fins

6. Many fishes have bodies covered by ____, which protect the body and reduce friction as they swim through the water. scales

7. A row of tiny sense organs along each side of a fish’s body is called the lateral line system.

8. Most fish breathe by using their gills.

9. ____ are organs that remove oxygen from the water. Gills

10. The ____ is a balloonlike organ that is filled with oxygen and other gases from the bloodstream. swim bladder

11. Amphibian means “double life.”

12. Tadpoles change into frogs by the process of metamorphosis.

13. _____ have special jaws with five joints that allow them to open their mouths wide and swallow very large prey. Snakes