Which phylum includes jellyfish, corals, and sea anemones?

• A. Cnidaria
• B. Chondrichthyes
• C. Chordata
• D. Cryptic Coloration

Answer: (A)

Cnidaria are animals defined by cnidocytes, specialized stinging cells used to capture prey, and a simple body plan with radial symmetry. Jellyfish, corals, and sea anemones all belong to this phylum. They are diploblastic, with two tissue layers, and have a gastrovascular cavity rather than a through gut. Their forms include the free-swimming medusa (jellyfish) and the polyp (sea anemones and many corals), with corals often building colonial calcium carbonate structures. The other options refer to entirely different groups or concepts: Chondrichthyes are cartilaginous fishes with backbones, Chordata includes animals with a notochord at some life stage, and cryptic coloration is a camouflage strategy, not a taxonomic group.