求解gwd一道旧题

宋痂岛__

GWD5-Q16:
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?D   正确：C

A.Once introduced into southern Europe, maize became popular with landowners because of its high yields relative to other cereal crops.X
B.Maize grown in the Americas contained more niacin than maize grown in Europe did.X
C.Traditional ways of preparing maize in the Americas convert maize’s 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 pellagra’s link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person.X

当时在CD中犹豫了很久 最终还是成功地选错了..... 希望有人帮忙解答一下~

Raymonduke

这题我感觉应该是楼主没看懂题吧。 题干是玉米包含了维他命N，但是在玉米里的这种维他命不能被人类吸收。 缺乏维他命N就会使人得P的病。当玉米从美国传到欧洲的时候，欧洲人迅速把玉米当成了主食，而那些主要以玉米为食物的欧洲人得了P的病。 而在美国，这些以玉米为主要食物的美国人没得这种病。  问解释？
得病的原因肯定是缺乏维他命N，而欧洲人得了肯定是缺，而美国人不缺。 只要能说明这一项就行了。

Raymonduke

如果是D的话，说南方的欧洲人既吃玉米又吃富含N的食物。 说明了维他命N的重要性，但是没能解释美国人为什么没得P病。 不能解释。