In order to develop chicken pox, one must be exposed to the virus that causes chicken pox. Note, however, that not everyone who is exposed to the virus is affected. In other words, the virus is a
A) risk factor.
B) contributory cause.
C) sufficient cause.
D) necessary cause.

Question

Quizplus · Accepted Answer

A necessary cause is a condition that must be present for a disease to occur. In this case, exposure to the virus is necessary to develop chicken pox, but not everyone exposed will develop the disease, indicating it is not a sufficient cause.

In Order to Develop Chicken Pox, One Must Be Exposed