Across
- 3. an internal skeleton, such as the bony or cartilaginous skeleton of vertebrates.
- 4. a flattened circular organ in the uterus of pregnant eutherian mammals, nourishing and maintaining the fetus through the umbilical cord.
- 7. System a system of canals in echinoderms containing a circulating watery fluid that is used for the movement of the tentacles and tube feet.
- 8. An air-breathing egg characterized by a shell and extraembryonic membranes.
- 9. an animal lacking a backbone
- 10. The freely-swimming, umbrella- or disk-shaped gelatinous form of Cnidarians
- 16. is an internal gas-filled organ that contributes to the ability of many bony fish to control their buoyancy, and thus to stay at their current water depth without having to expend energy in swimming.
- 19. an organism that regulates its internal temperature by exchanging heat with its surrounding environment
- 20. (of an animal) shed old feathers, hair, or skin, or an old shell, to make way for a new growth.
- 21. a rigid external covering for the body in some invertebrate animals, especially arthropods, providing both support and protection.
Down
- 1. a form of symmetry in which the opposite sides are similar
- 2. a tough elastic tissue composing most of the embryonic skeleton of vertebrates
- 5. Glandular organ located on the chest.
- 6. the arrangement of body parts around a central axis
- 11. dependent on or capable of the internal generation of heat.
- 12. the condition of having both male and female reproductive organs.
- 13. The hollow, columnar, sessile form of Cnidarians
- 14. two parts of something are not exactly the same
- 15. Having a backbone
- 17. the assemblage of organisms inhabiting the seafloor
- 18. a form of asexual reproduction in which a new individual develops from some generative anatomical point of the parent organism.