True or False: The nematodes are classified as flat worms.

Nematodes are not classified as flatworms; they belong to a different group known as roundworms. The key distinction between flatworms and roundworms lies in their body structure. Flatworms, which belong to the phylum Platyhelminthes, have a flattened, bilateral body plan and lack a true body cavity. In contrast, nematodes, classified under the phylum Nematoda, have a cylindrical, elongated body that is round in cross-section and possesses a pseudocoelom, a type of body cavity that is not completely lined by mesoderm. This difference in anatomy is fundamental in distinguishing these two groups of worms. Therefore, the classification of nematodes as flatworms is inaccurate.