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
50
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
By1800morethanathousandsteamengineswereinuseintheBritishIsles,
Wal-Martdoesn’tjustwantyoutobuygasandgroceriesatitssuperstorest
UsingYourTumble-Drier(滚筒烘干式洗衣机)ControlsTimer(计时器)Con
PASSAGETWO[br]Whatdoes"dualstudies"inPara.5mean?Apprenticeshipinaco
PASSAGETWO[br]Whatisthedifferencebetween"gentleman-in-waiting"and"jour
A.贵州、云南、陕西 B.湖南、山西、河南 C.四川、辽宁、陕西 D.湖南
按照《证券金融监督管理条例》,证券金融公司的设立和解散由()决定。A.国务院
甲与乙签订一份借款合同,其中约定乙将自己的钻戒质押给甲作为担保。之后乙并未将钻戒
标志线的端线应与道面边线垂直,允许偏差为()。A.±1° B.±2° C.
某医师拟比较四组人群血型分布(A、B、AB和O型)的差别,适宜的统计分析方法为(
最新回复
(
0
)