How do marine polychaetes use chitin hardened body parts?

Marine polychaetes utilize chitin-hardened body parts, such as their setae and parapodia, for various functions. These structures provide support and rigidity, aiding in movement and burrowing through sediment. The hardened setae also serve as a defense mechanism against predators. Additionally, these adaptations help polychaetes anchor themselves in their habitats and enhance their feeding strategies by allowing them to manipulate their environment.