These days, drug companies and health professionals alike are focusing their attention on cholesterol in the blood. ...

Naz on November 11, 2013

This is a Must Be True question consisting of a set of facts. Remember, the passage is going to 100% support the correct answer. We know from the argument that the more cholesterol we have in our blood, the higher the risk that we shall die of a heart attack. We know that heart disease (of which heart attacks are included since heart attacks are a type of heart disease) kills more North Americans every year than any other single cause. And we are then given three factors, smoking, drinking, and exercise (all aspects of one's lifestyle) that can influence levels of cholesterol in the blood. If these factors can influence levels of cholesterol, then they can also influence the risk that we shall die of a heart attack, meaning they can influence the risk that we shall die of heart disease (seeing as heart attacks are a type of heart disease).

(A) is incorrect because we know that the more cholesterol we have in our blood, the higher the risk that we shall die of a heart attack. However, if a person has low blood cholesterol, that does not necessarily mean that that person's risk of fatal heart disease is low. There are many types of fatal heart disease and many different causes. Even if his lower cholesterol brings his risk of dying from a heart attack down, it may not necessarily bring his risk of having clogged arteries or weak aortic walls down.

(B) is incorrect because we have not been given any information to lead us to the conclusion that smoking in moderation can entail as great a risk of fatal heart disease as does heavy smoking. We have no information on the levels of smoking and their respective effect on the risk of fatal heart disease. All we have been told about smoking in the stimulus is that it is one of at least three factors that influence levels of cholesterol in the blood.

(C) is incorrect because the facts in the passage do not support this. We know that heart disease kills more North American every year than any other single cause. We cannot conclude merely from the fact that high cholesterol influences the risk of dying from a heart attack that a high-cholesterol diet is the principal cause of death in North America.

(D) is incorrect because while the last sentence tells us that smoking does influence levels of cholesterol in the blood, nothing in the passage supports the claim that this is "the only way" that smoking increases one's risk of fatal heart disease. Therefore, we cannot conclude this answer choice.

(E) is CORRECT because, as the passage stated, we know that smoking, drinking and exercise (all aspects of one's lifestyle) can each influence levels of cholesterol, which, in turn, increases one's risk of dying of a heart attack, a type of heart disease. Note that the answer choice says "can be." It is not saying that it "must be" altered, merely that it is a possibility. All the information in the passage supports this. As you can see this is the only answer choice that "must be" true: it must be true that "the risk of fatal heart disease CAN be altered by certain changes in lifestyle."

Hope that was helpful. Let me know if you have any more questions!