Women"s fertility is determined in large part at birth. They are bom with their total number of reproductive cells, which normally influences the age at which menopause—the shutting down of female reproductive system—begins. But in the 1990s, researchers proposed that if a child"s energy is depleted by malnutrition, disease, or other factors, he or she would be less fertile as anadult. By using the natural experiment of migration, researchers demonstrated how differences during childhood do alter the course of reproduction in adult women. Biological anthropologist Gillian Bentley of Durham University in the UK and colleagues compared levels of reproductive hormones in 250 Bangladeshi women, including women who migrated from Sylhet, Bangladesh to London; women who stayed in Sylhet; and Bangladeshi women born in London. In the first stage of their study, they found that women who migrated from Bangladesh as children had higher levels of reproductive hormones in their saliva than women who lived in Sylhet, but less than women bom in London. This had a direct effect on fertility: Migrant women in London had an 11% higher rate of ovulation—discharging of mature ovum—during their lives than did women in Sylhet, the team reported in 2007. The team has now studied 900 women between the ages of 35 and 60 to see if the beginning of menopause varies between migrants and women in Sylhet. Bentley presented preliminary results from their measurement of hormones that regulate the maturation of reproductive cells and are indirect indices of how many ova they can still produce. Her team found that migrants enter menopause later than did women who stayed in Bangladesh but earlier than did those born in London. "The adult migrants seem to be sensitive to improved conditions," says Bentley. The group is trying to find out which environmental factors in Bangladesh lower growing girls" fertility. All the Bangladeshi women in the study came from middle-class, land-owning families, who grew up with adequate calories. However, girls growing up in Bangladesh were probably exposed to more infectious diseases during crucial developmental years. So, they may have had to make tradeoffs among using energy to grow, to maintain their bodies, or to maximize their reproductive potential as adults. Bentley plans to test that idea next year when her team returns to Bangladesh to see if girls there suffer from more diseases than do those in London. "In other words," says Bentley, "where you spend your childhood influences adult reproductive function."

单选题 According to the text, which of the following factor in childhood will probably cause an adult to be less fertile?

单选题 In Paragraph 2, Gillian Bentley"s research showed us that

【正确答案】 D

【答案解析】解析：事实细节题。根据第二段可得知本特利研究的内容和结论是妇女由于生长环境的不同导致生育能力的不同，并且着重提到了这些研究对象童年的生长地，故选D。A项断章取义，没有提到比较对象，不能得出此结论；根据倒数第二句可知出生在伦敦的妇女的生育能力比从锡尔赫特移民过来的妇女要高，B项与此相反，故排除；C项说的是研究的表象，且没有提到童年生长环境和生育能力的关系，表达不够准确全面。

单选题 Migration here in the experiment is

【正确答案】 C

【答案解析】解析：推理判断题。通过分析本特利的两个研究可发现移民妇女这一组是作为一个独立的研究对象出现在研究过程中的，与其他两组对象有着相同的地位，因此C项“一个独立的变量”为正确选项。根据原文可知，移民跟测量没什么关系；他们是研究对象不是研究方法；而且研究人员没有刻意去控制他们，所以也不是“控制条件”，故A、B、D三项均不正确。

单选题 What could be concluded from the research on the menopause of women?

【正确答案】 A

【答案解析】解析：观点态度题。根据第三段倒数第二句话可得出生长在不同地区的妇女进入更年期的时间也不同，而更年期的早晚会影响妇女的生育能力，因此A项符合。文中未提及更年期与生殖激素水平的关系，故排除B项；C项说更年期表明成年女性的成熟，这是对文中“生殖激素可以调节生殖细胞的成熟”的歪曲理解；D项中的in their birth place不够准确，因为这其中可能包括了出生在伦敦的孟加拉妇女。