Sample Response: A nudibranch would be classified as an invertebrate. It has a jellylike body with no backbone and no endoskeleton. It has a short life cycle. Though colorful, it is not as complex as a vertebrate.
Nudibranchs are are invertebrates just like crustaceans, mollusks, sponges, corals, sea cucumbers, etc. These marine animals don't have a backbone, which is a characteristic of invertebrates.
