Passage Summary: Doctors are worried about cholesterol because it leads to heart attacks, which are a major killer, and we know that habits like exercise and smoking change how much cholesterol is in our blood.

Reasoning: High blood cholesterol increases heart attack risk, heart disease is a leading cause of death, and lifestyle factors like smoking, drinking, and exercise affect cholesterol levels.

Analysis: Since this is a 'Must be True' question, we aren't looking for a flaw; we are looking for a logical deduction. We have a chain of information: lifestyle factors (smoking, drinking, exercise) influence cholesterol levels, and cholesterol levels influence the risk of a fatal heart attack. Therefore, it is a safe bet that these lifestyle factors can influence the risk of dying from a heart attack. Look for an answer that connects these dots without adding any outside information or 'strong' language like 'guarantees' or 'only.'