What feature is found in all mollusks bilateral symmetry radial symmetry a hinged shell or the ability to swim?

All mollusks exhibit bilateral symmetry, meaning their body can be divided into two mirror-image halves along one plane. While some mollusks, such as bivalves, have hinged shells, this trait is not universal among all mollusks. Radial symmetry and the ability to swim are also not characteristics found in all mollusks. Thus, bilateral symmetry is the defining feature present in all members of this diverse phylum.