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  3. Women’s fertility is determined in large part at birth. They are born with their total number of reproductive cells, which norma

Women’s fertility is determined in large part at birth. They are born with their total number of reproductive cells, which norma

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问题     Women’s fertility is determined in large part at birth. They are born 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 an adult 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 born 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."
In Paragraph 2, Gillian Bentley’s research showed us that
选项 A、women staying in Sylhet had a high level of reproductive hormones.
B、women born in London were less fertile than those migrates from Sylhet.
C、reproduction level of adult women varied in different regions.
D、where you spend your childhood might affect the fertility of adult women.
答案D
解析 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。
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