A. The monocausal model of disease states that a sufficient putative cause must be present under certain circumstances for a disease to occur, thus demonstrating that every disease has only one cause. The first problem with this model according to Broadbent (2009:302-311), is that this model does not justify the restriction it places on the number of causes of a disease. The second problem highlighted by Broadbent (2009:302-311) is that of failing to classify diseases caused by genetic disorders alongside those that are the result of hereditary dispositions. Third, Broadbent (2009:302-311), states that this model does not take into account cases where the cause of a disease is present, and yet an individual with this cause is healthy and is not affected by the cause. For example, a woman who became known as Typhoid Mary lived for many years with typhus bacteria but did not get typhoid fever, even though the people she infected died. So it shows that even though typhoid Mary had the cause of the disease which was typhoid bacteria, she was healthy and unaffected...