A. The mono-causal model of disease states that there must be a sufficient putative cause present in certain circumstances for a disease to occur, thus showing that each 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 imposes on the number of causes of an illness. The second problem that Broadbent (2009: 302-311) shows is that of his inability to classify diseases caused by genetic disorders among those that result from hereditary dispositions. Third, Broadbent (2009: 302-311) states that this model does not take into account cases in which the cause of a disease is present, and yet an individual with that cause is healthy and unaffected. by the cause. For example, a woman known as Typhoid Mary lived for many years with typhoid bacteria, but did not get typhoid fever, even though the people she infected died. So this shows that even though typhoid Mary had the cause of the illness which was typhoid bacteria, she was healthy and unaffected....