From 1900 until the 1930s, pellagra, a disease later discovered to result from a deficiency of the vitamin niacin, was common am

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问题 From 1900 until the 1930s, pellagra, a disease later discovered to result from a deficiency of the vitamin niacin, was common among poor cotton farmers in the United States whose diet consisted mostly of corn, the least costly food they could buy. Corn does not contain niacin in usable form. Curiously, during the Depression of the early 1930s, when cotton’s price collapsed and cotton farmers’ income declined, the incidence of pellagra among those farmers also declined.
Which of the following, if true, most helps to explain the decline in the incidence of pellagra?

选项 A、When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.
B、People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency.
C、Until 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.
D、Effective treatment for pellagra became available once its link with niacin was established.
E、In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable.

答案A

解析 Argument Construction
Situation The disease pellagra, which is due to a deficiency of the nutrient niacin, was common among poor cotton farmers in the United States during the early part of the 20th century, until the early 1930s. The diet of these farmers consisted mostly of the inexpensive grain corn, which lacked niacin in a form that can be absorbed by the body However, when the cotton price collapsed during the Great Depression in the early 1930s, the incidence of pellagra decreased among these farmers.
Reasoning What might explain the decline in incidence of pellagra among the cotton farmers during the Great Depression, despite the likelihood that the farmers would have experienced an increase in poverty? It may seem "curious" that a disease associated with malnutrition and poverty would become less common during a severe economic downturn. Our task is to find something that would explain this curious fact.
A Correct. The passage suggests that the pellagra of the farmers was due to their diet of mostly corn, which they purchased. However, this option indicates that, during the time that the farmers grew much of their own food during the Great Depression, the diet of the farmers changed significantly and had greater variety. This point, together with the fact that pellagra among the farmers decreased during this time, suggests that the decrease in pellagra among the farmers was due to their growing their own food.
B Although this option mentions another aspect of nutritional deficiency due to narrowness of diet, the question to be addressed is about nutritional deficiency of niacin rather than of protein.
C The belief that pellagra was an infection transmitted from person to person would not explain why the incidence of pellagra decreased among the farmers during the Great Depression.
D This option might explain the decrease in incidence of pellagra among the farmers if it was true that the link of pellagra with niacin deficiency was discovered before the decrease in incidence of pellagra among the farmers. Given the information provided, we don’t know whether or not this is true.
E This option might help to explain the decline in pellagra if it was the case that the cotton farmers started to eat corn that had been processed in the manner of the people in parts of Mexico. However, we have not been given a reason to suppose that the farmers ate corn that had been processed in this way.
The correct answer is A.
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本试题收录于: GMAT VERBAL题库GMAT分类
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