Ascaris belong to Phylum Aschelminthes. The main distinguishing feature is that sexes are separate. These are known as roundworms as they show presence of body cavity. These show well presence of organ system and hence digestive system is also complete. These can be free living or parasitic in nature. The parasites can be in ectoparasites or endoparasites depending on whether they are on the host or inside the host. These show presence of pseudocoloem as mesoderm is in the form of pouches. Hence true coloem is absent and these organisms also lack metamerism.