Which of the following organisms is an example of a coelenterate?

The Hydra is an example of a coelenterate, which is a term often used to refer to a group of animals known as Cnidarians. This group includes organisms such as jellyfish, corals, and sea anemones, all characterized by their radial symmetry, a body plan that features a simple sac-like structure, and the presence of specialized cells called cnidocytes, which contain stinging organelles. Hydras are freshwater coelenterates that exhibit both polyp and medusa forms in their life cycle, although they primarily exist in the polyp stage. Their ability to regenerate and reproduce both sexually and asexually makes them an interesting study subject in biology.

In contrast, earthworms belong to the phylum Annelida, grasshoppers are members of the class Insecta within the phylum Arthropoda, and sharks are part of the phylum Chordata. These organisms possess various body plans and characteristics that differentiate them from coelenterates, primarily lacking the key features of cnidarian anatomy such as cnidocytes and the typical radial symmetry associated with coelenterates.