Polychaete worms are a diverse group of segmented worms belonging to the class Polychaeta within the phylum Annelida. They are primarily found in marine environments, living in various habitats such as sandy, muddy, or rocky substrates. Polychaetes are characterized by their numerous bristle-like structures called chaetae, which help them move and anchor themselves in their surroundings. These worms exhibit a wide range of sizes and colors, with some species reaching lengths of over a meter. Polychaetes play essential roles in the ecosystem, contributing to nutrient cycling and serving as a food source for various marine animals, including fish and crustaceans. Their unique adaptations and behaviors make them an important part of marine biodiversity.