首页
登录
职称英语
The timing of flu season is a little hard to predict. Part of what makes it
The timing of flu season is a little hard to predict. Part of what makes it
游客
2024-01-15
17
管理
问题
The timing of flu season is a little hard to predict. Part of what makes it unpredictable is that scientists still don’ t understand exactly why we have one at all. There have been lots of theories:
One theory is that people spend more time indoors, with the windows closed, breathing each other’ s air. Other scientists have argued that cold of winter weakens our immune systems. A third theory is that the flu virus lives in the cold, dry air, but suffers in the warm, humid air.
For a while, scientists had a hard time testing these theories: they needed to run experiments, but researchers aren’ t allowed to infect humans with illnesses, and most lab animals aren’t affected by the flu the same way people are.
In 2007, a medical researcher named Peter Palese found an 80-year-old journal article that reported that guinea pigs (豚鼠)get infected and pass on the flu just like humans.
Palese decided to test Theory 3. The research team led by Palese ran several experiments and in each experiment, they injected half the guinea pigs with influenza A (the common flu), and put them in a box next to a box of uninfected animals.
At a temperature of 41 degrees, all four of the exposed guinea pigs caught the flu, but when Palese repeated the experiment at 68 degrees, only one of the animals was infected. And when he ran the test at 86 degrees, none of the exposed animals got sick.
The researchers also ran experiments where they varied the humidity in the room but kept the temperature constant: the drier the air, they found, the more animals got sick.
Palese’ s study showed that the influenza virus does spread more effectively in cold, dry air. [br] At a temperature of 68 degrees, how many guinea pigs were infected?
选项
A、None.
B、Only one.
C、Half of them.
D、All of them.
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3365875.html
相关试题推荐
Whenshedoessomething,Mrs.Brownfeelsthatherlittlechildisalways______.
Aseasonticket______theholdertomakeasmanyjourneysashewishedwithinthe
Therewerea______numberofstudentsontheplayground.A、fewB、littleC、shortD、
Whenshewasbusytidyingtheroom,herlittlekidisalways______.A、underwayB
Itisdifficultforustoexplainphenomenathatwehavelittleor______directk
______carewouldhavepreventedit.A、AfewB、AlittleC、FewD、LittleB本题考查形容词用法。
Thelittleboysawtheplane______andburstintoflames.A、completeB、compelC、cr
Mary:Yourlittleboyhasdoneagoodjobatschool.Eva:______A、Yes,youare
Makesureallthemembersofourclubarriveontime,______therewillbelittle
Thedogfrightenedthelittlegirl______crying.A、intoB、toC、withD、forA本题考查动
随机试题
Differentthingsusuallystandfordifferentfeelings.Red,forexample,is
在CT扫描前需要大量饮水的检查部位是A.膀胱 B.肾脏 C.肺 D.肝胆
下列各项关于审计机关权限中,凡是涉及管理、分配、使用公共资金、国有资产、国有资源
有关血栓闭塞性脉管炎的治疗,下列哪项是错误的A.应用高压氧治疗,增加肢体供氧量
男,14个月,因发热1天,抽搐1次而就诊。无呕吐及腹泻,发热当时39.5℃,抽搐
营业收入审计目标包括()。A:收入真实性B:收入完整性C:收入分类正确性D
各种运输方式内外部的各个方面的构成和联系,就是( )。 A.运输系统
以下不属于鸡血藤的主治证的是A.肢体瘫痪 B.月经不调 C.风湿痹痛 D.
下列标石格式,可指示接头位置的是( )。
下列哪个是焊缝表面不允许存在的缺陷()。A.表面气孔 B.咬边 C.砂
最新回复
(
0
)