Across
- 4. body parts are arranged in a circle around a center point
- 7. animal that generates its body heat from the inside
- 8. skeleton is on the outside of the body
- 9. connects fetus to mother for nutrient and gas exchange
- 11. can be split into left and right sides in only one way
- 12. organs that exchange carbon dioxide for oxygen in water
- 13. animal that heats its body from its environment
- 15. shedding and replacing of an exoskeleton, skin, or feathers
Down
- 1. does not have a backbone
- 2. an organism that lives in or on another organism, harming it
- 3. cannot be cut into equal halves
- 5. skeleton is on the inside of the body
- 6. has a backbone
- 10. protective membrane that surrounds the embryo
- 14. changes in form as animal becomes an adult