Every year, thousands of shells wash up on beaches around the world. Have you ever found a shell and wondered where it came from or what its function once was? These shells come from a large phylum of animals known as mollusks which includes members...

A shell is a hard, rigid outer layer developed by a wide variety of different animal species, including mollusks, crustaceans, turtles and tortoises, armadillos, and microscopic organisms. Shells are used for protection, locomotion, defence, structure...