Final answer:
The pocket-book clam primarily engages in filter-feeding through its gills, which also assist in respiration.These particles are then moved to the mouth by cilia, thereby providing the organism with nourishment. Additionally, these gills facilitate respiration by allowing for the exchange of oxygen and carbon dioxide with the surrounding water.
Step-by-step explanation:
The pocket-book clam performs filter feeding as its primary function. Bivalves, which include clams, scallops, oysters, and mussels, have evolved to possess specialized gills that play a crucial role in this process. When water is drawn into the clam, it passes over the gills where mucus traps food particles. These particles are then moved to the mouth by cilia, thereby providing the organism with nourishment. Additionally, these gills facilitate respiration by allowing for the exchange of oxygen and carbon dioxide with the surrounding water.