首页
登录
职称英语
The chemical adenosine is released by brain cells when those cells are active. A
The chemical adenosine is released by brain cells when those cells are active. A
游客
2024-01-12
33
管理
问题
The chemical adenosine is released by brain cells when those cells are active. Adenosine then binds to more and more sites on cells in certain areas of the brain, as the total amount released gradually increases during wakefulness. During sleep, the number of sites to which adenosine is bound decreases. Some researchers have hypothesized that it is the cumulative binding of adenosine to a large number of sites that causes the onset of sleep.
Which of the following, if true, provides the most support for the researchers’ hypothesis?
选项
A、Even after long periods of sleep when adenosine is at its lowest concentration in the brain, the number of brain cells bound with adenosine remains very large.
B、Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells.
C、Besides binding to sites in the brain, adenosine is known to be involved in biochemical reactions throughout the body.
D、Some areas of the brain that are relatively inactive nonetheless release some adenosine.
E、Stress resulting from a dangerous situation can preserve wakefulness even when brain levels of bound adenosine are high.
答案
B
解析
Argument Evaluation
Situation Adenosine is released from brain cells that are active. The amount of adenosine released increases during wakefulness, and it binds to more and more sites on cells in certain brain locations. The number of sites to which it is bound decreases during sleep. Researchers have hypothesized that the cumulative binding of adenosine to many sites causes the onset of sleep.
Reasoning Which of the five pieces of information most strongly supports the hypothesis? If the hypothesis is correct, then some factor that impedes the binding of adenosine should be closely associated with wakefulness. Therefore, finding some such factor, and observing that it is accompanied by wakefulness when the factor operates, would tend to confirm the hypothesis.
A Without further, more specific information, this piece of information suffices neither to confirm nor to refute the hypothesis.
B Correct. A finding that caffeine, known to induce wakefulness, inhibits adenosine from binding to sites on brain cells helps confirm the hypothesis.
C This piece of information lacks a clear relevance to the hypothesized impact on sleep, and therefore does not help confirm the hypothesis.
D This information lacks a clear relevance to the hypothesized impact on sleep, and therefore does not help confirm the hypothesis.
E What this indicates is that stress may impede the hypothesized sleep-inducing effect of adenosine. It does not refute the hypothesis but does not confirm it either.
The correct answer is B.
转载请注明原文地址:https://tihaiku.com/zcyy/3357374.html
相关试题推荐
Researchersconcludedthatlowlevel______tothechemicalwasunlikelytocaus
Thechemicalfactorywastorndown______protectingtheenvironment.A、inspiteof
Inaforest150deerwerecaught,taggedwithelectronicmarkers,thenreleased.
Naturallyoccurringchemicalscannotbenewlypatentedoncetheirstructureshav
Passengersmustexitairplanesswiftlyafteraccidents,sincegasesreleasedfol
Mostgeologistsbelieveoilresultsfromchemicaltransformationsofhydrocarbon
Proponentsoforganicfarmingclaimthatusingchemicalfertilizersandpesticid
Aworldwidebanontheproductionofcertainozone-destroyingchemicalswouldpr
Aplaceboisachemicallyinertsubstanceprescribedmoreforthementalrelief
Acidrainandsnowresultfromthechemicalreactionsbetweenindustrialemissio
随机试题
FortwocandidatesYourcompanyisplanningtoestablishafactorywithanother
LisaFryandPaulaTurnergrewupacrossthestreetfromeachotherinTwin
Chinaisfamous________theGreatWall.A.
G蛋白分子特性()。A.由2个亚基组成 B.有7个跨膜α-螺旋 C.有l个
政府统计机构包括()。A.政府综合统计机构和政府分支统计机构 B.国家统计局和
小儿风寒感冒的治法宜选用A、辛温解表 B、辛凉解表 C、清暑解表 D、清热
患者,男性,70岁。因突然停用糖皮质激素出现哮喘重度发作,表现为端坐呼吸、明显发
建筑施工图中,用来表式建筑物位置的是()。A:总平面图 B:平面图 C:立
()是指儿童偏向于对一类刺激物注意得多,而在同样情况下对另一类刺激物注意得
( )是公司的最高权力机构。A.董事会 B.监事会 C.股东大会 D.经
最新回复
(
0
)