Across
- 3. lay eggs that are leathery
- 6. lay eggs without shells
- 8. These invertebrates have hair for protection.
- 11. fins that work together as sets
- 12. Amphibian eggs hatch into _____.
- 13. Two wings are used for this.
- 15. Some reptiles _____ eggs in sand.
- 16. Birds and mammals have hearts with this many chambers.
- 17. _____ have internal skeletons for support.
- 19. Fish have hearts with this many chambers.
Down
- 1. Mammal eggs begin _____ the mother's body.
- 2. _____ allow fish to get oxygen from water.
- 4. Amphibians have slick, porous _____.
- 5. Two _____ are used for hopping or standing.
- 7. Scales can _____ for protection.
- 9. lay jelly-covered shells in water
- 10. Birds reproduce by means of eggs with _____ shells.
- 12. Reptiles have hearts with this many chambers.
- 14. how mammals feed their infants.
- 18. Fish have hearts with this many chambers.