Mussels are molluscs and are related to water snails. Because their shells are divided into two halves, they are called bivaldes. The shell protects the soft body of the animal. A powerful foot enables the animal to

Parasites are animals that live at the expense of other animals. They rob the host animal of nourishment and often cause it to become sick. However, in other types of relationships, different animals can help one another.

A marsupial is a mammal whose young are born in an extremely immature state. The newborn undergoes most of its development attached to one of its mother's nipples and nourished by her milk. Females of most

 After insects, molluscs form the largest group of animals. Molluscs have soft, muscular bodies, often covered by a protective shell. Some, such as snails, move on a muscular foot , which can be withdrawn into the shell for protection. Other, sea-dwelling molluscs, such as squid and scallops, take in water and squirt it out to jet-propel themeselves along. Many snails are an important food for fish, birds, and crutaceans , such as crazy fish and lobster. Many people consider the helix garden snail, Which is shown as escargot, a great delicacy.