Several recent studies have found that moderate drinkers of alcohol have lowered levels of heart disease risk than non-drinkers. it has been hypothesized that moderate drinking may reduce stress which in turn may lead to a reduction in the risk of heart disease. in this example lowered stress levels would be considered a(n) variable.

The answer is byour welcome: )

(a) is not correct because one does not get increased cholesterol  from lifting weights.(b) is not correct because lifting weights cannot reduce the risk of a hereditary disease.(c) is not correct because back pain isn't a benefit! and plus, if he lifts weights properly, he should not have back pain.(d) is the correct answer because his ligaments will gain mass, making it easier for him to carry heavier weights and he will also be stronger!