Animal Crossword Puzzle

4. the vascular organ in most mammals that unites the fetus to the uterus of the mother.
5. dependent on or capable of the internal generation of heat.
7. an animal lacking a backbone
10. one of two principal body types occurring in members of the invertebrate animal phylum Cnidaria
13. a gas-filled organ in bony fish that helps them regulate buoyancy
14. a type of egg that are laid by reptiles, birds, and some mammals
15. an animal of a large group distinguished by the possession of a backbone or spinal column
16. An organism whose body temperature is largely determined by heat exchange with its surroundings
18. an internal skeleton, such as the bony or cartilaginous skeleton of vertebrates.
20. shed old feathers, hair, or skin, or an old shell, to make way for a new growth.
21. lack of equality or equivalence between parts or aspects of something

1. an abnormal growth of tissue that projects from a mucous membrane
2. a unique hydraulic system found in echinoderms
3. an organism that possesses both male and female reproductive organs or tissues
6. a tough, flexible connective tissue that plays a crucial role in the musculoskeletal system
8. plant and animal symmetry in which similar parts are arranged in a balanced way around the center of the body
9. having or developing buds
11. a hard, external covering that provides support and protection for many invertebrate animals
12. the property of being divisible into symmetrical halves on either side of a unique plane.
17. anything related to or occurring on the bottom of a body of water
19. modified sweat glands that produce and secrete milk for nourishing infants.