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Across 1. controls involuntary actions 4. carry blood toward the heart 5. circulatory system in which the blood cells never leave the blood vessels 7. tiny vessels that allow the exchange of gases and nutrients 8. soft tissue inside the bone that produces blood cells 9. located in the brain and coordinates a creature's response to info 12. coordinates vital funtions and transport signals from the brain to the spinal cord 13. fertilization in which a male fertilizes eggs outside of the female 14. development of an egg that hatches inside the female 20. receive signals from receptors in the eyes 21. heart chamber from which blood is pumped out 22. fresh water to salt water back to fresh water 23. lobes that receive signals from receptors in the nose

Down 2. skeleton inside 3. supports and protects the head and neck 4. offspring gains nutrients from the mother through a placenta 6. lacking an internal mechanism for regulating body heat 10. extremely low metabolism and respiration accompanied by lower than normal body temperatures 11. development of an egg that hatches outside the female 15. segments of bone arranged into a backbone 16. carries blood away from the heart 17. fertilization in which a male place sperm inside the female's body 18. mixture of salts phospholipids that aid in the breakdown of fat 19. rod of fexible material that runs the length of a creatures body 22. heart chamber that receives blood