Animals like annelids, arthropods, chordates, larvae of echinoderms, etc., where the body can be divided into identical left and right halves in only one plane, exhibit bilateral symmetry. When any plane passing through the central axis of the body divides the organism into two identical halves, it is called radial symmetry. Coelenterates, ctenophores, and echinoderms have this kind of body plan. Sponges are mostly asymmetrical, i.e., any plane that passes through the center does not divide them into equal halves.