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
2025-03-03
8
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/3980437.html
相关试题推荐
_________studentwithalittlecommonsenseshouldbeabletoanswerthequesti
Mary:Yourlittleboyhasdoneagoodjobatschool.Eva:________A、Yes,youare
Althoughtheaccidentdidverylittle______tothecar,Istillsuggestthatyou
Whenshedoessomething,Mrs.Brownfeelsthatherlittlechildisalways______.
______studentwithalittlecommonsenseshouldbeabletoanswerthequestion.A
Thetimingoffluseasonisalittlehardtopredict.Partofwhatmakesit
Thetimingoffluseasonisalittlehardtopredict.Partofwhatmakesit
Waltlikedonelittlemousebetterthananyoftheothers.Thislittleanimalga
Hewashealthyandstrong,buthehadverylittleformaleducation.他身体健康、强壮,但是接受
Don’tleavematchesorcigarettesonthetablewithinthe______oflittlechild
随机试题
WhyWeDon’tLikeEnglishClassesI.People’smisunderstandi
图示桁架结构杆①的轴力为: A.-2PB.-PC.-P/2
以最大能力法计算项目贷款偿还期,是指项目本身投产以后产生的可还款资金偿还项目贷款
关于化学课程与教材,下列说法正确的是( )。A、教材和课本是一回事情 B、一
患者精神恍惚,心神不宁,悲忧善哭,时时欠伸,舌淡苔薄白,脉弦细。其治法是A.益气
在正常乳腺细胞学涂片中不出现的细胞是A.导管上皮细胞B.吞噬细胞C.泡沫细胞D.
患者,男,50岁。平常嗜烟酒,有胆囊结石病史,昨晚饮酒和暴食后,出现左上腹疼痛,
高压熔断器熔断1次,运维人员应立即汇报值班调控人员申请将电压互感器停运。
由于看到鸟的飞翔而发明了飞机,这类创造活动的心理影响机制是( )。 A.功
基金评级不只是对基金本身的评价,还可以兼顾到对基金公司投资能力的评价。()
最新回复
(
0
)