What type of parasite do nematodes classify as?

Nematodes are classified as roundworms, which distinguishes them from other types of parasitic worms. They belong to the phylum Nematoda and are characterized by their elongated, cylindrical shape, which is typical of roundworms. This classification reflects their anatomical features and biological characteristics, such as a complete digestive system and a body structure that is not flattened, unlike flatworms (which would fall under the category of options A, C, and D).

Roundworms, including many nematodes, can be free-living in soil and aquatic environments or parasitic in various animal hosts, where they can cause diseases. Understanding this classification can help in the study of parasitic infections and the types of treatments, such as anthelmintics, that are effective against these specific organisms.