A muscular organ that is used for locomotion and takes a variety of forms depending on the animal.<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> | A muscular organ that is used for locomotion and takes a variety of forms depending on the animal.<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> |