How are the feeding methods used by sea urchins and sea stars similar and different?

Sea urchins use five-part jawlike structures to scrape algae from rocks. Sea lilies use tube feet along their arms to capture floating plankton. Sea cucumbers move like bulldozers across the ocean floor, taking in sand and detritus. Sea stars usually feed on mollusks such as clams and mussels.

Explanation:

answer; ///(b) it is composed of four protein chains and four heme groups;