Which term refers to the class that includes clams, oysters, and scallops?

Which term refers to the class that includes clams, oysters, and scallops?

• A. Gastropoda
• B. Bivalvia
• C. Cephalopoda
• D. Polyplacophora

Answer: (B)

The main idea tested is understanding mollusk classification by body plan. Clams, oysters, and scallops belong to the class Bivalvia because they have two shells (valves) hinged together that enclose a laterally compressed body and function mainly as filter feeders. This two-shell design is a defining feature that sets them apart from other mollusk groups. For context, gastropods like snails usually have a single shell (or none) and undergo torsion, cephalopods like octopuses and squids have a prominent head with arms and are active predators, and polyplacophorans (chitons) have eight plates on their back.

The main idea tested is understanding mollusk classification by body plan. Clams, oysters, and scallops belong to the class Bivalvia because they have two shells (valves) hinged together that enclose a laterally compressed body and function mainly as filter feeders. This two-shell design is a defining feature that sets them apart from other mollusk groups. For context, gastropods like snails usually have a single shell (or none) and undergo torsion, cephalopods like octopuses and squids have a prominent head with arms and are active predators, and polyplacophorans (chitons) have eight plates on their back.