There is no exact answer to this question. There are thousands of different species that range from less than a centimeter to the giant clam weighing hundreds of pounds.
bivalves
bivalves
The kind of mollusk includes clams and oysters is called bivalves.
it is called a bivalve
Clams are bivalves
Bivalves are mollusks with two shells, such as a clam. A univalve is a mollusk with one shell, such as a snail.
Gastropods, or slugs and snails, as opposed to molluscs with two shells which are bivalves.
Bivalves, univalves, and cephalopods are all types of mollusks. So are gastropods.
Every mollusk except slugs, which have evolved to not need a shell, has a shell. Snails, clams and other bivalves have an external shell. Octopi, squid and cuttlefish have an internal shell.
Bivalves are mollusks with two hinged shells that they can close for protection. They come in various shapes and sizes, and their shells can have different colors and patterns. Bivalves do not have a distinct head or radula but have a muscular foot for movement and feeding.
Clams, oysters, and mussels are in the shellfish family, under the subheadings of mollusks and bivalves. Mollusks include abalone and scallops as well as clams, oysters, and mussels. Bivalves are any creature with a soft body that lives between two hinged shells.
The gills of bivalves that I have seen, I would describe as looking like a piece of screening covered with cilia.