<p>The important thing to remember here is that &nbsp;seashells are not past of the mollusks living body. It is primarily made up mostly of calcium carbonate and very little protein (less than 2%).&nbsp;</p>
<p>The mollusks secrete the protein and the calcium carbonate that layers up to form the shell. This results in the body of the creature serving as the inner mold for the outer shell. The secretions keep on happening during the life of the mollusk and as the creature grows, so does the shell surrounding it.&nbsp;</p>
<p>The shell itself is not a living tissue but its essential for the mollusks survival. This means that any damage to it also repaired through secretions of minerals by the mollusk. Once the animal dies, it discards the shell and without anything to guide them, the shells just sit on the ses/ocean floor, until they are pushed to the shore by the underwater currents.</p>