Which of the following statements best encapsulates the relationship between stress and physical illness according to psychoneuroimmunologists?

a) Stress compromises the body's immune system, leaving a person vulnerable to illness.
b) Stress increases the production of natural killer cells, which causes cell death and leads to illness.
c) Stress causes high blood pressure, heart disease, and cancer.
d) Stress has no direct relationship to physical illness, though physicians tell us that these things are related so that we will be more willing to take unnecessary medications.

ANS: A, Although stress has not been found to directly cause illness, it does appear to rob the body of its ability to fight illness effectively.