Final answer:
Brittle stars have long, thin, flexible arms that are used for movement and feeding.
Step-by-step explanation:
Brittle stars have long, thin, flexible arms that are sharply demarcated from the central disk. These arms are used for movement, grasping prey, and lashing out or wrapping around objects. Unlike sea stars, brittle stars do not have plump arms and their arms do not contain any organs. Instead, their arms are simply used for locomotion and feeding.