Which types of worms are classified as nematodes?

Nematodes are a diverse group of worms characterized by their round, elongated bodies and a complete digestive system. This classification includes several types of parasitic worms that significantly impact human health. The correct option identifies pinworms, whipworms, threadworms, and Ascaris, which are all well-known nematodes.

Pinworms, caused by Enterobius vermicularis, are commonly found in children and are known for causing anal itching. Whipworms, from the genus Trichuris, are associated with gastrointestinal symptoms. Threadworms, or Strongyloides stercoralis, can cause serious infections, especially in immunocompromised individuals. Ascaris lumbricoides, the giant roundworm, is another common nematode that can lead to significant health issues by obstructing intestinal flow.

In contrast, cestodes (flatworms like tapeworms) and trematodes (flukes) are separate categories of parasitic worms. They possess distinct morphological and biological characteristics that differentiate them from nematodes. Hookworms, while also categorized as nematodes, do not encompass the full range of nematodes and are thus not the most comprehensive answer. Therefore, identifying pinworms, whipworms, threadworms