Nematoda, commonly known as roundworms, are a diverse group of unsegmented worms found in various environments, including soil, freshwater, and marine habitats. They play essential roles in ecosystems, such as decomposing organic matter and serving as a food source for other organisms. These organisms exhibit a wide range of sizes and shapes, with some being microscopic while others can grow several meters long. Many nematodes are free-living, but some are parasitic, affecting plants and animals, including humans. Their adaptability and resilience make them a fascinating subject of study in ecology and agriculture.