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题库 / OG2015-CR-49
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?
Once introduced into southern Europe, maize became popular with landowners because of its high yields relative to other cereal crops.
Maize grown in the Americas contained more niacin than maize grown in Europe did.
Traditional ways of preparing maize in the Americas convert maize's niacin into a nutritionally useful form.
In southern Europe many of the people who consumed maize also ate niacin-rich foods.
Before the discovery of pellagra's link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person.
类比推理：
P：欧洲人吃了会得病
C：美国人吃了不会得病
答案要么同时提到类比的两者，要么给出两个案例平行等价的案例C
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A选项：玉米被介绍到欧洲南部后成为地主当中流行的食物，因为其相对其他谷物产量高。没有提到两个案例。
B选项：在美洲种植的玉米比在欧洲种植的玉米含有较多的烟酸。提到了两个案例，但题目中说明了烟酸不能直接被人体吸收。
C选项：在美洲，烹调玉米的传统方式将玉米中的烟酸转换成营养可用的形式。同时提及了两个案例，并且给出了两者不相似的原因：烹调方式不同（CQ1相似性问题：两者真的相似吗？是否存在某些重要差异）。
D选项：在欧洲南部的许多吃玉米的人也吃烟酸丰富的食物。没有同时提到两者。
E选项：发现糙皮病与烟酸有关之前，它被广泛认为是可以从人到人传播感染的。与案例无关。
欧洲吃了会得病 美国吃了不得病。
B but not in a form the body can absorb.所以无法解释
C 本来不能吸收，现在可以吸收了
D 不能解释美国人不得病
因果. CQ1: 干扰因素问题
不应该是类比吗？
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