All the coelenterates exhibit [[1]] level of organisation.

All the coelenterates exhibit tissue-level organization. They have specialized cells organized into tissues, but they lack complex organ systems. The tissues include the epidermis, gastrodermis, and mesoglea. Coelenterates are also characterized by the presence of stinging cells called nematocysts, which they use for defense and capturing prey. Examples of coelenterates include jellyfish, sea anemones, and corals.