Mollusks have a head area and a foot area and, often a hard outer shell. Inside their ORal cavity, they have a mouth with a ribbon of teeth and a radula (a tonguelike organ). If they live on land they have a forward foot that moves them. Their gills are in a groove surrounding their feet-like structures. They have a tissue called the mantle that surrounds their body. SPECIALIZED glands in their bodies EXCRETE a substancethat hardens and forms their outer shell.
Mollusks have bilateral symmetry, meaning in the center of their bodies they are symmetrical. If divided in two they would look exactly the same. Radial symmetry is when an organism can be divided equally from the center, or axis, the difference is that Bilateral symmetry is when an organism can be divided into mirrored parts.