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  3. Any hope of a fountain of youth to stop people from getting older is a long way off with science just beginning to understand th

Any hope of a fountain of youth to stop people from getting older is a long way off with science just beginning to understand th

admin2016-02-26  72
问题     Any hope of a fountain of youth to stop people from getting older is a long way off with science just beginning to understand the complex genetic, physical and hormonal causes of aging. But experts said there were interesting targets for study, including genes involved in Alzheimer’disease, the hormone DHEA and the role of exercises in keeping people young.
    Steven Lamberts and colleagues noted that levels of DHEA were much lower in older people. One study in adults showed taking DHEA tablets " induced a remarkable increase in perceived physical and physiological wellbeing in both men and women without having an effect on sex. " Other studies on rats showed giving them DHEA could prevent obesity and diabetes. But they said much more study was needed.
    Cable Finch and Rudoph Tanzi said it was conceivable that genetic engineering experiments could transfer genes from one species to another to alter life span. However, it seems unlikely that a few genes determine the 25 fold difference in life spans between rats and humans. An instructive example is the 10-fold difference in life spans of female worker bees and queens of the same genotype, which show much slower aging during life spans of many active years of egg production. The difference—what the bees were fed as juveniles.
    One interesting genetic candidate was the apoE gene, mutations of which are linked with Alzheimer’s disease. One version of this gene does seem to be linked with long life, although many more studies are needed.
    For those who do not want to wait, Lamberts’team said exercise can be key to preventing the frailty that aging brings. Loss of muscle strength is an important factor in the process of frailty. One study in home for the elderly showed a sedentary lifestyle greatly contribute to this. Supervised resistance exercise training could double muscle strength and significantly increase gait velocity and stair-climbing power. This demonstrates that frailty in the elderly is not an irreversible errect of aging and disease and can be reduced and perhaps even prevented.
In the example cited by Finch and Tanzi, life span was most likely affected by______.
选项 A、transferring certain genes
B、different strains between species
C、nature of one’s lifelong work
D、the diet one takes
答案C
解析 信息归纳题。文章第三段最后一句话说道，一个有意义的例子就是雌蜂的寿命是同基因类型的蜂王寿命的十倍。这表明雌蜂在积极地大量产卵期间，生命老化得较慢。由此可推知，答案为C。
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