A characteristic of the phylum coelenterata is that

A characteristic of the phylum Coelenterata, also known as Cnidaria, is that they possess a gut with a single opening. This means that the same opening that takes in food also expels waste. They are a simple, yet diverse group of aquatic animals that includes jellyfish, sea anemones, and corals. They have a relatively simple body plan, with a central body cavity called a coelenteron, tentacles, and stinging cells called cnidocytes. Most of them are marine and have radial symmetry. The gut with a single opening is a unique feature that distinguishes them from other phyla.