首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Women live longer than men because they are spoiled for choice. That is the startling conclusion of an international group of sc
Women live longer than men because they are spoiled for choice. That is the startling conclusion of an international group of sc
admin
2010-05-26
83
问题
Women live longer than men because they are spoiled for choice. That is the startling conclusion of an international group of scientists who say they have found the cause of female longevity.
They say females have two separate cell lines in their bodies, while men have only one. Women in old age can "choose" the more robust (强壮的) of these lines and survive for many more years.
Why there should be such a persistent cross-cultural gap between the life spans of the sexes has baffled scientists until now. In a paper in the journal Blood, and reported in the current issue of New Scientist, researchers at Odense University in Denmark and Ulleval University Hospital in Norway point to a key difference in the sex-determining chromosomes (染色体) found in the cells of men and women.
Every cell in a woman’s body has two X chromosomes, one inherited from her mother and the other from her father. In each cell, one of these two X chromosomes is switched off. This means that a woman is a mosaic (混合体) of two cell lines: one derived from her father’s X chromosome, the other from her mother’s. By contrast, every cell in a man’s body has an X and a Y chromosome, neither of which is turned off. He has only one cell line. This difference could be crucial in determining the long-term health of men and women, scientists concluded, and so they decided to examine cells taken from young women.
They found an even division between their two different lines. However, when they looked at elderly females they found their bodies now favoured one set of cells at the expense of the other line. "This suggests that one of the cell lines is ’better’ than the other," say the researchers. In other words, women’s bodies may select the more vigorous of the two cell lines and allow it to predominate the twilight of their years, giving them a crucial advantage over men, who have no chance of choosing the healthier of two sets of cells.
"The twilight of their years" (Line 5, Para. 5) refer to______.
选项
A、their old years
B、their young years
C、their good years
D、their bad years
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/AcV7777K
0
大学英语四级
相关试题推荐
Onanycollectingtrip,obtainingtheanimalsis,asarule,thesimplestpartofthejob.Assoonasthelocalpeoplediscover
A、Marriageneedstobeimproved.B、Peoplegetcaughtupwithcareers.C、Peopleshouldbebusywithraisingkids.D、Marriageneed
Thepartoftheenvironmentalmovementthatdrawsmyfirm’sattentionisthedesignofcities,buildingsandproducts.Whenwed
Thepartoftheenvironmentalmovementthatdrawsmyfirm’sattentionisthedesignofcities,buildingsandproducts.Whenwed
Thepartoftheenvironmentalmovementthatdrawsmyfirm’sattentionisthedesignofcities,buildingsandproducts.Whenwed
Inmanycountries,itisnot【B1】______forfamiliesofdifferent【B2】______tolivetogetherinsharedspace.However,intheUni
A、Howtosucceedincareer.B、Howtoresolvepersonalproblems.C、Howtodealwithbusiness.D、Howtomakemoney.B
A、Theyplayagainsteachotherinordertogetthebestscore.B、Theywanttogetsomeexercises.C、Theywanttowinaprize.D、
ThenumberofspeakersofEnglishinShakespeare’stimeisestimatedtohavebeenaboutfivemillion.Todayitisestimatedtha
随机试题
感官鉴定的敲听鉴别法主要用于检查罐头有无胖听现象。
对于远中游离端义齿的制作下列哪项是错误的
被称为“阳脉之海”的是
在保险理赔过程中,投保人张某与保险人对于保险合同中的“不可抗拒的原因”的理解发生争议,两种说法都能讲通。张某的理解更有利于保护自己的利益。法院在判决时应该采取()。
生态安全有以下()特点。
设计交底的过程包括以下几项:(1)由设计单位介绍设计意图、结构特点、设备性能、制造及工艺要求、技术措施和有关注意事项及关键问题;(2)由制造单位提出图纸中存在的问题和疑点以及需要解决的技术难题;(3)通过三方研究和商讨,拟定出解决的办法,并写出会议纪
背景资料:某施工单位承接了一座二级公路隧道,该隧道为单洞2车道,设计净高5m,净宽12m,总长686m,穿越的岩层含有少量煤层,裂隙发育,设计采用新奥法施工。洞口段围岩为较软岩或软硬岩互层,且以软岩为主,岩体较完整,中薄层状结构,属于Ⅳ
“报刊的有机运动”是马克思提出的关于报刊报道新闻的过程理论,它被通俗地解释为新闻真实是一个动态的过程。很多时候,在事件发生初期,由于报道的不深入,没有充分的消息源,新闻传达给受众的信息往往是片面的,受众的判断也建立在这种片面的事实上。这正是新闻传播的一种特
某批发商店的经理正考虑一新的销售计划。已知每个顾客购买额的均值为200元,标准差为15元。如果随机抽取36名顾客,试计算平均购买额超过204元的概率。
欧阳修有一篇名作对无形的秋声进行了形象的描绘,此文的名称是《_______》。
最新回复
(
0
)