首页
登录
职称英语
Women live longer than men because they are spoiled for choice. That is the
Women live longer than men because they are spoiled for choice. That is the
游客
2023-07-26
56
管理
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. [br] The difference in the sex-determining chromosomes is that______.
选项
A、a woman inherits X chromosomes from her mother while a man from his father
B、a woman inherits Y chromosomes from her mother while a man from his father
C、a woman has an X and a Y chromosome while a man has two of them
D、a woman has two X chromosomes while a man has an X and a Y chromosome
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2870972.html
相关试题推荐
Cathyturneddownthewell-paidjobbecause______(要求经常出差).itinvolvedtoomany
FriendshipandLivingLongerDoyouwanttobeheal
FriendshipandLivingLongerDoyouwanttobeheal
FriendshipandLivingLongerDoyouwanttobeheal
FriendshipandLivingLongerDoyouwanttobeheal
Forvisitorsjust______(想游览)ThreeGorges,thecruisefromchoice.toYichangis
Foodwhichiskepttoolongdecaysbecauseitisattackedbyyeasts(酵母菌),m
Foodwhichiskepttoolongdecaysbecauseitisattackedbyyeasts(酵母菌),m
Foodwhichiskepttoolongdecaysbecauseitisattackedbyyeasts(酵母菌),m
Cultureshockissonamedbecauseoftheeffectithasonpeoplewhenriley
随机试题
于沉入桩沉桩顺序的说法,正确的有()。A.宜先大桩后小桩,先长桩后短桩
28岁,患慢性盆腔炎2年,反复发作。此次入院因高热3天,伴下腹痛。妇科检查:子宫
图示结构不属于拱结构的是()。A. B. C. D.
旅行社单项服务的对象主要针对的是()。A:全包价游客 B:自助游散客 C:半
如图9所示流程图,输出的结果是( )。 A.19 B.100 C.120
因债务人或交易对手未能履行合同所规定的义务.影响金融产品价值,从而给债权人或金融
洋金花成人的一日常用量按照2010版《中华人民共和国药典》是A:0.3~0.6g
下列情形中,当事人无需申请房屋所有权转移登记的是()。A:互换 B:以房屋出资
在契约型基金中,基金份额持有人只能通过召开()对基金的重大事项作出决议。 A
信托关系下,以自己的名义管理或者处分信托财产的是()A.受托人 B.监督人
最新回复
(
0
)