What type of animals are classified under phylum Coelenterata?

Animals classified under phylum Coelenterata, also known as Cnidaria, include more complex organisms such as jellyfish, corals, and sea anemones. This group is characterized by a body structure that features a central gastric cavity and a simple tissue organization with specialized cells called cnidocytes, which contain stinging structures used for defense and capturing prey. Coelenterates display radial symmetry and can exist in either polyp or medusa forms, showcasing their versatile life cycles.

The complexity of these organisms goes beyond that of sponges, which are simpler and lack true tissues and symmetry. In addition, flatworms, roundworms, and segmented worms belong to different phyla and do not possess the key characteristics that define coelenterates. Thus, identifying jellyfish and similar creatures as members of phylum Coelenterata accurately reflects their biological classification and distinguishing features.