Question

When an individual is exposed to Factor A, Factor B or Factor C the disease develops. Then Factor A is:

		a necessary and sufficient cause
		a necessary, but not sufficient, cause
		a sufficient, but not necessary cause
		Neither necessary not sufficient

Answer 1

In the present scenario , factor A is a necessary but not sufficient cause. It means that factor A alone cannot cause the disease and multiple factors are required to cause the disease. In that case one factor will be considered as not sufficient but a necessary one.

The first option , necessary and sufficient cause means without that factor disease never develops and with that factor disease always develops. But in the present situation with only factor A disease won't develop. It needs all three.

The next one is , a sufficient but not necessary cause means that this factor alone can cause disease and also without this factor other factors can cause the disease. But here without factor A , disease won't happen and only factor A won't result in disease.

The last option is neither sufficient nor necessary , which means that , the factor alone cannot cause the disease and it's not necessary to have that factor for the disease to occur. In the present scenario , factor A alone can't cause disease but A is needed for the disease to occur.