What class of helminths includes organisms such as hookworms and pinworms?

The correct answer is based on the classification of helminths, or parasitic worms. Nematodes, also known as roundworms, are the class that includes both hookworms and pinworms.

Hookworms belong to the genus Ancylostoma and Necator, while pinworms are primarily represented by Enterobius vermicularis. These organisms are characterized by their elongated, cylindrical bodies and lack of distinct segmentation, which differentiates them from other classes of helminths.

Cestodes are flatworms, commonly known as tapeworms, and are distinguished by their segmented bodies, while trematodes, or flukes, have a complex life cycle that often involves multiple hosts. Platyhelminths is a broader phylum that encompasses both cestodes and trematodes but does not include nematodes. Therefore, identifying the specific class that encompasses hookworms and pinworms leads to the conclusion that nematodes is the correct classification.