Cholesterol, which is a known factor in coronary heart disease and stroke, needs a carrier, known as a lipoprotein, to transport it through the bloodstream. Low-density lipoproteins (LDLs) increase the risk of coronary heart disease and stroke, but we can tentatively conclude that high-density lipoproteins (HDLs) help prevent coronary heart disease and stroke. First, aerobic exercise increases one' s level of HDLs. Second, HDL levels are higher in women than in men. And both aerobic exercise and being female are positively correlated with lower risk of coronary heart disease and stroke. Each of the following, if true, strengthens the argument EXCEPT: ['A high level of HDLs mitigates the increased health risks associated with LDLs.', 'Persons who are overweight tend to have a higher risk of early death due to coronary heart disease and stroke, and tend to have low levels of HDLs.', 'HDLs, unlike LDLs, help the body excrete cholesterol.', 'HDLs are less easily removed from the bloodstream than are LDLs.']