Which term includes clams and oysters with two hinged shells?

Which term includes clams and oysters with two hinged shells?

• A. Cephalopods
• B. Mollusk
• C. Bivalve
• D. Gastropod

Answer: (C)

Two hinged shells define a group called bivalves. Clams and oysters are classic examples of bivalves, which are a class of mollusks—the broader phylum that also includes snails and squids. The two-shell design sets them apart from other mollusks: cephalopods like octopus and squid have a very different body plan with no two-shell protection, and many gastropods (snails, slugs) have a single shell or none at all. Inside their two shells, bivalves typically filter feed and use adductor muscles to open and close the shells, with the hinged pair serving as the protective boundary for their soft bodies.