animal kingdom

3. Excretory structures in annelids that remove metabolic wastes.
6. Specialized cells in cnidarians that contain stinging organelles.
8. External ears found in mammals.
10. A rasping, tongue-like organ in molluscs used for feeding.
12. Organisms that emit light due to chemical reactions within their body.
13. Common chamber for the digestive, excretory, and reproductive tracts in some animals.
15. Small, flexible appendages in echinoderms used for locomotion and feeding.
17. Development involving a distinct larval stage before reaching adulthood.
18. Excretory structures found in insects and terrestrial arthropods.
19. Organisms that maintain constant body temperature regardless of the environment.
20. Segmented body organization, seen in annelids and arthropods.

1. Development without a larval stage; young ones resemble the adult.
2. The central cavity in sponges through which water flows.
4. An anterior elongated structure in some invertebrates used for feeding or sensory roles.
5. Organisms that give birth to live young instead of laying eggs.
7. A structure in hemichordates similar to the notochord.
9. An organism that has both male and female reproductive organs.
11. Species in which individuals are either male or female.
14. Biological process involving drastic change in body form from larva to adult.
16. Class of jawless vertebrates like lampreys and hagfish.