Which Mollusc Clade Includes Members That Undergo Embryonic Torsion

Question

Which mollusc clade includes members that undergo embryonic torsion?
A) chitons
B) bivalves
C) gastropods
D) cephalopods

Accepted Answer

Gastropods are the only mollusc clade that includes members that undergo embryonic torsion, a process that rotates the visceral mass and mantle 180 degrees, resulting in the anus and mantle cavity being located above the head.