Final answer:
Brittle stars utilize their long arms for feeding by grasping prey, impacting the benthic ecosystem as predators and scavengers.
Step-by-step explanation:
Brittle stars have a unique feeding behavior that sets them apart from their echinoderm relatives. Their long, thin arms, which are clearly distinguished from their central disk, are used for grasping prey instead of locomotion. They do not have a water vascular system for moving and unlike sea stars, their arms do not contain any organs. Feeding behavior in brittle stars can directly impact the surrounding ecosystem, as their method of capturing food can affect the distribution and abundance of prey species. They play a role in the benthic community as predators and scavengers, contributing to the flow of energy and nutrient cycles within their habitat.