A researcher investigates an organism found on the ocean floor. The organism is asymmetrical. It lacks a body cavity, body tissues, organs, and a nervous system. The researcher finds that the organism can fully regenerate itself if parts of its body are broken off. Into which phylum should the researcher classify the organism?

The correct answer is option A, that is, Phylum Porifera.  

The species of Phylum Porifera are aquatic, that is, mostly marine. They exhibit cellular grade of the body, they are diploblastic animals with asymmetrical symmetry. They lack body cavity and exhibits a holozoic mode of nutrition with intracellular digestion.  

They lack circulatory and nervous system and possess the tendency to regenerate their parts of the body. The organisms in phylum Porifera exhibits both asexual and sexual mode of reproduction.