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  3. Why past generations regarded women as the weaker sex is a mystery to anyone who has examined the question objectively, for they

Why past generations regarded women as the weaker sex is a mystery to anyone who has examined the question objectively, for they

admin2016-11-09  45
问题     Why past generations regarded women as the weaker sex is a mystery to anyone who has examined the question objectively, for they are far stronger than men—outliving them in pretty well every society in the world. Partly that is because men are more violent, and their violence is largely directed at other men. But partly it is physiological. Men seem to wear out faster than women do. Yet no one knows why.
    Madeleine Beekman of the University of Sydney and her colleagues, however, have a hypothesis. They think at least some of the blame lies with subcellular structures called mitochondria (线粒体), which provide the body with its power by burning glucose and using the energy thus released to make a molecule that is biology’s universal fuel.
    Mitochondria are amusing. They are descendants of bacteria that teamed up with the ancestors of animal and plant cells about a billion years ago. They retain their own genes, which is where problems start. To avoid fights between genetically different mitochondria in the same cell, most species have arranged for their mitochondria to come from only one parent—usually the mother so that a male’s mitochondria are stuck in an evolutionary dead end. They can neither evolve in male-specific ways nor be passed on to the next generation.
    Male and female physiologies are sufficiently similar for this not to be a central problem, but Dr. Beekman thinks it may matter at the margins. She observes that one disease, caused by a faulty mitochondrial gene, occurs in only 10% of women whose cellular power-packs include the damaged gene, but in 50% of men whose mitochondria are so hindered. The gene in question, in other words, is less likely to harm a woman than a man. She then lists a lot of other diseases, including ones far commoner that sometimes have a mitochondrial component, and speculates that some of these may prove to be either more common or more serious in men than in women. As far as her literature search can show, this is not something that has yet been looked into.
    Part of the reason for this absence of information may be that few doctors think like evolutionary biologists, so they fail to ask appropriate questions. Dr Beekman’s hypothesis may turn out to be wrong, but sounds remarkably plausible and certainly worth investigating.
This passage is intended to explain________.
选项 A、how different genes combine to determine human lifespan
B、what factors have left females weaker than males
C、whether human health depends on mitochondria alone
D、why women outlive men from an evolutionary perspective
答案D
解析 没把握选择时，可用排除法。首先，文章没有论述不同基因对寿命的影响。其次，文章要说明的是女性并不是the weaker sex，恰恰相反，作者得出的结论是某些方面“男不如女”。文章简要介绍了线粒体的功能和影响，但并未说明人的健康仅仅取决于线粒体。人们公认女性的寿命比男性长，但迄今没有令人信服的解释。Madeleine Beekman的发现证明这与线粒体有关，为人们提供了一个新的研究角度。   
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