Animal Crossword Puzzle

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