Roundworms, also known as nematodes, are a diverse group of worms notable for their cylindrical, elongated bodies that taper at both ends. They are ubiquitous in the animal kingdom, found in various environments from marine to terrestrial habitats. Many species are free-living, feeding on bacteria, fungi, or small particles in their environments, but some are notorious parasites in plants, animals, and humans. Roundworms play a significant role in the ecosystem by helping in the decomposition process and nutrient cycling. Parasitic species, however, can cause various diseases in their hosts, such as ascariasis in humans, which is caused by the roundworm Ascaris lumbricoides. These organisms are characterized by their simple body plan, lacking a circulatory and respiratory system, with their body cavity filled with fluid under high pressure, which serves as a hydrostatic skeleton.