What organ of both fish and clam has the same function as the papulae of the starfish?

The organ in both fish and clams that serves a similar function to the papulae of starfish is the gills. Gills are responsible for gas exchange, allowing aquatic animals to absorb oxygen from the water and expel carbon dioxide. In starfish, papulae also facilitate gas exchange and help in excretion, functioning similarly to gills in terms of respiratory processes.