AP 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: -Porifera is mostly asymmetrical. Asymmetrical means that any plane traveling through the body’s central axis does not divide the organism into two equal halves.

Detailed explanation-3: -Only sponges (phylum Porifera) have asymmetrical body plans. Some animals start life with one type of body symmetry, but develop a different type as adults; for example, sea stars are classified as bilaterally symmetrical even though their adult forms are radially symmetrical.

Detailed explanation-4: -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-5: -Answer and Explanation: Animals in the phylum Porifera, most commonly known as the sponges, are asymmetrical.