Across
- 3. Bladder an internal gas bag helping fish float.
- 9. an animal without a backbone.
- 10. Symmetry body plan with matching left and right sides.
- 11. having no balanced body shape.
- 15. a free-swimming umbrella-shaped sea creature.
- 20. warm-blooded; controls body heat internally.
- 21. a support skeleton inside the body.
Down
- 1. tough, flexible tissue instead of bone.
- 2. Eggs shelled eggs that develop on land.
- 4. an animal with a backbone.
- 5. Vascular System water tubes used to move and eat.
- 6. having both male and female organs.
- 7. cold-blooded; relies on external heat.
- 8. shedding an old shell or skin to grow.
- 12. Glands milk-producing organs in mammals.
- 13. an organ supplying food to an unborn baby.
- 14. offspring growing directly off a parent.
- 16. a hard protective outer shell.
- 17. living on the water floor.
- 18. Symmetry body parts arranged around a central point.
- 19. a tube-like sea creature attached to a surface.