Animal Crossword Puzzle

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Across
  1. 2. an organism that regulates its internal temperature by exchanging heat with its surrounding environment
  2. 3. a plant having stamens and pistils in the same flower
  3. 4. a free-swimming sexual form of a coelenterate such as a jellyfish
  4. 5. a network of water vessels in the body, the tube feet being operated by hydraulic pressure within the vessels
  5. 7. the property of being divisible into symmetrical halves on either side of a unique plane
  6. 8. lack of equality or equivalence between parts or aspects of something
  7. 9. firm, whitish, flexible connective tissue found in various forms in the larynx and respiratory tract, in structures such as the external ear, and in the articulating surfaces of joints
  8. 13. a gas-filled sac present in the body of many bony fishes, used to maintain and control buoyancy
  9. 15. a solitary or colonial sedentary form of a coelenterate such as a sea anemone
  10. 16. a flattened circular organ in the uterus of pregnant mammals, nourishing and maintaining the fetus through the umbilical cord
  11. 18. dependent on or capable of the internal generation of heat
  12. 20. an internal skeleton, such as the bony or cartilaginous skeleton of vertebrates
Down
  1. 1. an animal lacking a backbone, such as an arthropod
  2. 4. shed old feathers, hair, skin, or an old shell, to make way for a new growth
  3. 6. an animal of a large group distinguished by the possession of a backbone or spinal column
  4. 10. An air-breathing egg characterized by a shell and extraembryonic membranes
  5. 11. a rigid external covering for the body in some invertebrate animals
  6. 12. the milk-producing gland of women or other female mammals
  7. 14. symmetry around a central axis
  8. 17. having or developing buds
  9. 19. of, relating to or occurring at the bottom of a body of water