Questions 21-25 refer to the following passage. Like all hormones, insulin has widespread and varied __21__ in the body even though doctors typically pay attention to only one of them: the facilitation of transport of glucose from the blood into the cells. We now know that insulin also __22__ the body to store up calories as fat, can promote arterial damage, and may even accelerate the growth of tumors. Moreover, in some people, frequent outbursts of insulin from the pancreas may encourage cells to decrease their __23__ to that hormone. By making fewer insulin receptors, they become insulin resistant. Insulin resistance is __24__ with stubborn obesity, abnormalities of blood fats, high blood pressure, adult-onset diabetes, and cardiovascular disease, including increased risk of death from heart attacks and strokes. Is it possible that all those satisfying, filling, life-sustaining carbohydrate foods that became available to us following the __25__ of starch-bearing plants are the root cause of these calamities? (Question 21)