罡哥gmat逻辑分类 解释类.pdf

罡哥GMAT 逻辑 解释类感觉 35 ．Maize contains the vitamin niacin, but not in a form the body can absorb. Pellagra is a disease that results from niacin deficiency. When maize was introduced into southern Europe from the Americas in the eighteenth century, it quickly became a dietary staple, and many Europeans who came to subsist primarily on maize developed pellagra. Pellagra was virtually unknown at that time in the Americas, however, even among people who subsisted primarily on maize. Which of the following, if true, most helps to explain the contrasting incidence of pellagra described above? A. Once introduced into southern Europe, maize became popular with landowners because of its high yields relative to other cereal crops. B. Maize grown in the Americas contained more niacin than maize grown in Europe did. C. Traditional ways of preparing maize in the Americas convert maizes niacin into a nutritionally useful form. D. In southern Europe many of the people who consumed maize also ate niacin-rich foods. E. Before the discovery of pellagras link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person. 36 ．Each year red-winged blackbirds stop in a certain region of Midland Province on their spring and fall migrations. In the fall, they eat a significant portion of the provinces sunflower crop. This year Midland farmers sought permits to set out small a mounts of poisoned rice during the blackbirds spring stop in order to reduce the fall blackbird population. Some residents voiced concern that the rice could threaten certain species of rare migratory birds. Nevertheless, the wildlife agency approved the permits. Which of the following, if true, most helps to justify the