This question asks you to compare how much different risk factors influence health. The best choice is the one that literally describes the factor with the largest impact on health outcomes. In health science, we think about how strongly a risk factor changes the likelihood of disease or poor health across people, often talking in terms of effect size or population impact. The option that states “a factor with the greatest influence on health” directly communicates that idea of magnitude, which is what the question is asking for. The other descriptions don’t address how powerful the influence is. Labeling something as primary or secondary describes its relationship or order among factors, not how strongly it affects health. Describing a factor as unchangeable focuses on whether it can be changed, rather than how much it affects health. So the option naming the greatest influence best matches the idea being asked.

LDL cholesterol, often called bad cholesterol, is a key factor in the development of atherosclerosis—the buildup of cholesterol-rich plaques inside artery walls. When these plaques form in the arteries that feed the heart, they narrow or block blood flow, raising the risk of coronary heart disease and heart attack. The other conditions listed—osteoporosis, asthma, and arthritis—are not driven by LDL levels in the same way, as they involve bones, airways, and joints, respectively. Keeping LDL in a healthier range helps protect heart arteries and lowers the risk of coronary heart disease.

Regular exercise helps you handle stress by boosting both physical fitness and mental well-being. When you stay active, your cardiovascular system gets stronger, energy improves, sleep often improves, and mood is lifted. These changes make it easier to cope with daily stress and bounce back from stressful events. Chemicals released during activity, like endorphins, contribute to a calmer, more positive mindset, reinforcing resilience. That combination—improved physical capability plus better mental state—best represents how exercise supports stress management. While hormones can rise briefly during a workout, the lasting impact is not higher stress hormones, but greater fitness and coping ability. Appetite changes or longer recovery times aren’t the central way exercise manages stress.

Muscular endurance means the ability to sustain repeated muscle contractions with lighter resistance, so you perform more repetitions per set. Very low reps—like three or six—primarily target strength or power, not endurance. Among the given options, nine is the smallest rep count that still aligns with endurance training within this context, making it the minimum you’d aim for in a set to develop endurance. You could progress by adding more reps or adjusting rest or load later, but nine reps is the baseline here.