单选题 A long-term health study that followed a group of people who were age 35 in 1950 found that those whose weight increased by approximately half a kilogram or one pound per year after the age of 35 tended, on the whole, to live longer than those who maintained the weight they had at age 35. This finding seems at variance with other studies that have associated weight gain with a host of health problems that tend to lower life expectancy.
Which one of the following, if true, most helps to resolve the apparently conflicting findings?

A、 As people age, muscle and bone tissue tends to make up a smaller and smaller proportion of total body weight.
B、 Individuals who reduce their cholesterol levels by losing weight can thereby also reduce their risk of dying from heart attacks or strokes.
C、 Smokers, who tend to be leaner than nonsmokers, tend to have shorter life spans than nonsmokers.
D、 The normal deterioration of the human immune system with age can be slowed down by a reduction in the number of calories consumed.
E、 (E) Diets that tend to lead to weight gain often contain not only excess fat but also unhealthful concentrations of sugar and sodium.

【正确答案】 C

【答案解析】[解析] 本题没有逻辑上严密的答案，通过对5个选项的分析我们发现(A)与本题的论述无关；(B)、(D)和(E)都倾向于解释其他的研究结果；相比之下，只有(C)选项能较好地解决本题中的两种研究结果的分歧。从抽烟者倾向于比不抽烟者瘦，即可推出35岁以后体重不断增长的人大都是不抽烟的人，因此尽管他们的体重增加会给他们带来一大堆的健康问题，但是他们的寿命还是比那些较瘦的，体重保持不变的人长，所以(C)有助于解决本题段落中的相互冲突的研究结果。