Clams, Mussels, & Snails

Clams, mussels, and snails are all mollusks. Mollusks are animals with a hardened outer shell and one foot made out of muscle. Snails have one shell on their backs. Mollusk shells come in all different shapes and sizes. Clams and mussels have two shells that open and close like a book. Many freshwater mussels are in danger of becoming extinct because of pollution.