NEET BIOLOGY

Detailed explanation-1: -Sponges are multicellular animals, unique in many ways. They are the only group of animals that can be classified as asymmetric, which means they possess no symmetry at all. There is no plane through their bodies where you could cut them in half to produce two mirror images.

Detailed explanation-2: -Sponges are asymmetrical because they are extremely simple. They live in the ocean, cannot move on their own, and have no complex organs or other features that higher-order animals have. Sponges are one of only a few types of animals classified as having asymmetry.

Detailed explanation-3: -Sponges are unsymmetrical or radially symmetrical, with many cell types but no distinct tissues; their bodies contain numerous pores and sharp protective spicules. Coelenterates (phylum Cnidaria) are radially symmetrical, with two tissue layers (ectoderm and endoderm) surrounding an all-purpose gastrovascular cavity.

Detailed explanation-4: -Only Demospongiae are asymmetrical whereas the other two classes have symmetrical body structure. Demospongia is the most abundant living sponges containing 90% of known species of sponges.

Detailed explanation-5: -Sponges are asymmetrical. Corals build colonies that are not symmetrical, but the individual polyps exhibit radial symmetry. Alpheidae feature asymmetrical claws that lack pincers, the larger of which can grow on either side of the body, and if lost can develop on the opposite arm instead.