college graduates generally live longer than people who dropout of high school. which of these conditions is most likely to explain these differences?

Several factors account for the longer life-expectancy of college-graduates:

More mental work and less physical work: people with college degrees mostly have jobs that do not require a lot of physical activity. Non-college graduates on the other hand, tend to work in jobs that require physical strain, for example: construction, mining, or even retail.Higher income and better medical care: most college-graduates make more money than non-college-graduates (exemptions exist). People with higher incomes can acess better medical care, and can afford more nutritious food.Less likely to smoke: research has consistently found that college graduates are less likely to smoke than non-college graduates. Smoking is very harmful to one's health and one of the leading causes of disability in the U.S.

You gotta post the test so we can answer it

Sometimes but itt depends, their is a lot if drugs on campus too so you really can't just say that