| − | An organism that causes disease.<ref>Wile, Dr. Jay L. ''Exploring Creation With General Science''. Anderson: Apologia Educational Ministries, Inc. | + | An organism that causes disease.<ref>Wile, Dr. Jay L. ''Exploring Creation With General Science''. Anderson: Apologia Educational Ministries, Inc. The most common pathogens are [[bacteria]](such as [[Escherichia coli|E Coli]], [[viruses]](such as the influenza virus), [[fungi]](such as [[Ringworm]]) and [[protozoa]](such as [[Giardia lamblia|Giardia]]). |