Concept:Ascaris belongs to phylum Aschelminthes (Nematoda), commonly called roundworms. These animals have a pseudocoelom (false coelom) and lack metameric segmentation.Explanation:Ascaris is a roundworm. Its body cavity is a pseudocoelom, not a true coelom. The body is not divided into segments (no metamerism). It is triploblastic, bilaterally symmetrical, and has a complete alimentary canal. The excretory system uses canals, and sexes are separate. Since it lacks a true coelom and metameric segmentation, option B is correct.Answer:B. presence of neither true coelom nor metamerism