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Across 1. The earliest vertabrates were _____________ fish. 4. _______ (type of cartilaginous fish) spend most of their time hunting. 7. Fish have a(n)__________ circulatory system. 9. Bony fish live in salt and ______ water. 11. The swim bladder contains gasses such as oxygen, nitrogen and ___________________. 14. The swim bladder helps a fish ____________ its body in different depts. 15. The ______ bladder is filled with gasses. 16. Sharks have ___________ fertilization. 17. _________ help fish swim. 20. Some countries are trying to stop ________________. 22. Fish are the biggest group of ____________. 23. The __________________ is the force that water exerts upward on any underwater object.

Down 2. Most fish have ____________________________. 3. Today, there are only about 60 _______ of jawless fish. 5. The ______ pumps in one continuous loop. 6. What do fish get their oxygen from? 8. Fish are in the phylum ________. 10. Jawless fish have no ____________. 12. Bony fish have skeletons made of hard _________. 13. The skeleton of a _________________ fish is made of cartilage. 18. The most familiar kind of fish are _________ fish. 19. What in a fish filters oxygen out of water? 21. True or false. Bony fish make up 95% o fish species.