Researchers have recently discovered that people with low

Question

Researchers have recently discovered that people with low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity. The researchers concluded from this experiment that the immune system protects against mental illness as well as against physical disease.

The researcher's conclusion would be most seriously weakened if it were true that 

(A) there was a one-year delay between the completion of a pilot study for the experiment and the initiation of the experiment itself

(B) people's levels of immune-system activity are not affected by their use of medications

(C) a few people with high immune-system activity had scores on the test of mental health that were similar to the scores of people who had normal immune-system activity

(D) people who have low immune-system activity tend to contract more viral infections than do people with normal or high immune-system activity

(E) high levels of stress first cause mental illness and then cause decreased immune-system activity in normal individuals

HIMALAYA · Answer

E. it says high levels of stress cause to have mental illness, which ultimately cause people to score much lower on tests of mental health.

segmoti · Answer

I will go with E. Mental illness itself causes the immune-system activity to decrease and seriously weakens the conclusion

keirin79 · Answer

E was my pick as well, but the OA is D.

Researchers have recently discovered that people with low

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