Nematoda

Members of the phylum Nematoda are roundworms, and many are microscopic.(c)They are autotrophs.
Roundworms have many of the same characteristics as flatworms; for example, bilateral symmetry and cephalization.(c)They are autotrophs. They also have a digestive tract open at both the mouth and the anus.(c)They are autotrophs. This tract is suspended in a body cavity that is said to be false, so it is called a pseudocoel.

Many species of roundworms are free-living organisms that help consume dead plant and animal matter.(c)They are autotrophs. Several parasitic roundworms cause human diseases, including trichinosis, hookworm disease, and elephantiasis.