首页
登录
职称英语
Henry III didn’t know much about biology. He went through six wives back in
Henry III didn’t know much about biology. He went through six wives back in
游客
2023-07-17
44
管理
问题
Henry III didn’t know much about biology. He went through six wives back in the 1500s, looking for one who could bear him a son. Seientists now know that it’s the father’s sperm, not the mother’s egg, which determines whether a baby is a boy or a girl. And last week researchers at the Genetics and IVF Institute, a private fertility (生育能力) center in Virginia, announced a new technique that will allow parents to choose the sex of their baby-to-be, before it has even been conceived. The scientist used a tiny laser deteetor to measure the DNA in millions of sperm ceils as they pass single file through a narrow tube, like cattle being herded through a corral (牲口栏). In a study published last week, "girl sperm," which has more DNA--the genetic material-- in eaeh cell, was collected, while "boy sperm" was discarded. And when purified girl sperm was used to impregnate (使受孕) a group of mothers, 15 of 17 resulting babies turned out to be girls.
The researchers say that "sex selection" can also double a mother’s chance of having a son and can be used to avoid genetic diseases that affect only one gender, such as hemophilia (血友病). But some experts, like New York University fertility specialist Dr. Jamie Grifo, worry that sex selection could lead to a kind of in uteri (子宫) discrimination, especially in cultures where sons are considered superior to daughters. "It’s valuing one gender over another," Grifo says. "I don’t think that’s something we should be doing." So far, patients at the institute have been asking for both boys and girls, in order to "balance" their families. And some ethics experts say that’s fine, as long as parents are just looking for a little gender variety. "If you have three boys, and you want a girl," says University of Texas reproductive-law professor John Robertson, "that’s not gender bias at all." [br] The DNA in the sperm cells can be measured ________.
选项
A、in the same way how the cattle are herded
B、when they pass through a tube one behind the other
C、after they pass through a laser tube
D、when they are scanned by a laser detector all at a time
答案
B
解析
解答本题的关键在于推断single file的意思。本句把精子通过试管的情形与牛群被赶入牲口圈的情形作对比,结合single一词本身的意思,可以推断single file是“一个接一个”的意思,只有选项B能表达这个意思,由此也可否定选项D。
转载请注明原文地址:https://tihaiku.com/zcyy/2845404.html
相关试题推荐
[originaltext]AdeadlyinfectiousoutbreaksweptthroughasmallcityinZa
[originaltext]AdeadlyinfectiousoutbreaksweptthroughasmallcityinZa
[originaltext]Throughouthistorymanhaschangedhisphysicalenvironmenti
LearningthroughTestsTakingatestisnotjustapassi
LearningthroughTestsTakingatestisnotjustapassi
LearningthroughTestsTakingatestisnotjustapassi
LearningthroughTestsTakingatestisnotjustapassi
LearningthroughTestsTakingatestisnotjustapassi
LearningthroughTestsTakingatestisnotjustap
LearningthroughTestsTakingatestisnotjustap
随机试题
Thebookisonthetopshelfandisoutof______.A、distanceB、reachC、handD、a
______thenumberofcars,hethought,therewerenotmanypeopleattheclubyet
Holdingontothebeliefthatchildrenwillshedtheir"babyfat"astheyge
HowtoReadLiteratureCriticallyThefour-stepmethod
Irecommendthattheplanning______untilallthematerialshavebeensupplied.A、
Forthispart,youareallowed30minutestowriteashortessay.Youshouldsta
患者,女,30岁,已婚。月经先后无定期,质稀、量少,腰痛,头晕,舌淡少苔,脉沉细
根据下列资料回答问题。 保险密度表示的是人均保费,那么河南当年的人口数
高速公路排水沟呈梯形断面,设计沟内水深1.0m,过水断面积W=20m2,湿周ρ
自海洋石油钻井平台、潜艇等超大型货物相继出现以来,半潜船才渐渐找寻到自己的用武之
最新回复
(
0
)