Explain how the nematodes occur?

Nematodes, also known as roundworms, are a diverse group of organisms that can be found in various environments, including soil, freshwater, and marine habitats. They occur in a wide range of ecological niches, where they play essential roles in nutrient cycling and decomposition. Many species are free-living, while others are parasitic, affecting plants, animals, and humans. Their occurrence is influenced by factors such as moisture, temperature, and the availability of organic matter.