animal crossword

4. a gas-filled organ in bony fish that helps them control buoyancy,allowing them to stay at a desired depth without expending energy on swimming
6. specialized, milk-producing organs found in female mammals, involved from modified sweat glands
7. the study of animals with backbones that live in marine environments
9. the process where marine arthropods like crustaceans shed their exoskeletons to allow for growth and development in the body
11. an organism that possesses both males and females reproductive organs
12. a unique hydraulic system found in echinoderms that function in locomotion, feeding and gas exchange waste transport using a network of fluid filled canals and tube feet
15. an internal skeleton such as the bony or cartilaginous of skeleton of vertebrates
17. a specialized organ that facilitates nutrient and gas exchange between a developing fetus and its mother
18. a tough, flexible, and elastic connective tissue that forms the skeletal structure of cartilaginous
20. a hard external covering that supports and protects the body of a animal
21. the study of animals with backbones that live in marine environments

1. a body plan where an organism can be divided into similar halves by multiple planes passing through a central axis
2. lack of equality or equivalence between parts or aspects
3. an organism's body plan where it can be divided into two roughly mirror-image halves along a single plane
5. an animal lacking a backbone like a arthropod,mollusk and annelid
8. an organism whose body temperature is primarily regulated
9. the free swimming, umbrella-shaped body form of certain cnidarian like jellyfish,that is characterized by tentacles and is the sexual reproductive stage in their life cycle
10. an animal that maintains a stable internal body temperature by generating heat through internal metabolic processes
13. a type of egg characterized by extra-embryonic membranes
14. a sessile, cylindrical body form found in cnidarians characterized by a mouth surrounded by tentacles at one end
16. a form of asexual reproduction where a new individual develops as an out growth or bud
19. the study of the organisms communities and ecosystems that inhabit the seafloor and the sediments