| − | A measure of the [[mass]] of [[organ|organisms]] within a region divided by the area of that region.<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> | + | A measure of the [[mass]] of [[organism|organisms]] within a region divided by the area of that region.<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> |