Polymorphism is a characteristic feature of which group of animals?

Explanation

Polymorphism is a characteristic in which animals of the same species exist in two or more distinct forms, each performing different functions. This feature is commonly found in members of the phylum Cnidaria, also known as Coelenterata. Cnidarians include animals such as hydra, jellyfish, and corals. In these animals, two main structural forms are seen: the polyp form and the medusa form. The polyp is usually cylindrical and attached to a surface, while the medusa is umbrella-shaped and free swimming. These two forms help the organism carry out different roles in feeding, protection, and reproduction. Some cnidarians may also have further specialized forms within colonies, such as in corals and Portuguese man-of-war, where certain individuals are responsible for feeding, others for defense, and others for reproduction. This variety of forms within a single species or colony is what defines polymorphism.