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Across 1. Today, there are only about 60 _______ of jawless fish. 4. Fish have a(n)__________ circulatory system. 5. The ______ pumps in one continuous loop. 6. Fish are the biggest group of ____________. 7. The earliest vertabrates were _____________ fish. 9. The ______ bladder is filled with gasses. 10. The most familiar kind of fish are _________ fish. 11. _______ (type of cartilaginous fish) spend most of their time hunting. 12. The swim bladder contains gasses such as oxygen, nitrogen and ___________________. 14. Some countries are trying to stop ________________. 16. True or false. Bony fish make up 95% o fish species. 17. What do fish get their oxygen from? 18. What in a fish filters oxygen out of water? 19. The swim bladder helps a fish ____________ its body in different depts. 20. _________ help fish swim. 21. The __________________ is the force that water exerts upward on any underwater object.

Down 2. Most fish have ____________________________. 3. Fish are in the phylum ________. 4. The skeleton of a _________________ fish is made of cartilage. 8. Bony fish have skeletons made of hard _________. 9. Jawless fish have no ____________. 13. Sharks have ___________ fertilization. 15. Bony fish live in salt and ______ water.