I have a new situation: Bob's parents were in their early 60's. He sent them to the doctor's for a routine check up. Dan, his dad, had very high cholesterol, while Mary, his mom , had normal levels in her blood.

But I can use this background: Cholesterol has been implicated in heart disease for decades. Atherosclerosis is a disorder of the arteries in which cholesterol and other materials are deposited on the interior of the arterial wall. These deposits lead to the formation of plaques that can restrict or even block the flow of blood through these blood vessels (see Figure below ). A decrease in the flow of blood can lead to high blood pressure and a lowered oxygen supply to the heart muscle. A complete blockage of blood flow to parts of the heart (a heart attack) can cause significant damage due to oxygen deprivation, in some cases leading to death.

What is an answer for this question: Which parent had fewer plaques that could restrict blood flow?
Mary
Dan's cholesterol level is higher, so he will have more plaque in his arteries. Since plaques can restrict blood flow to the heart muscle and lead to a heart attack, Dan must be at greater risk of having this happen than Mary, whose cholesterol levels are normal. So it would seem logical that Mary had fewer plaques than her husband (and Bob's father), Dan..