List the structural features of the various classes of molluscs.

Gastropods. The body of the molluscs is divided into a head, a leg and a torso, which is twisted into a spiral and immersed in a shell. Movement with the help of the leg, on which the whole body is located.
Bivalve. The difference in body structure lies in the absence of a head; it consists of a leg and a torso. Everything is immersed in the sink together. The movement is also with the help of the foot, but much slower, because the animal has to pull the entire shell along the substrate behind its leg.
Cephalopods. In most individuals, the body consists of a torso, a modified leg and head. The leg is a funnel and tentacles surrounding it. The movement is reactive, due to the sharp release of water from the funnel.