首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
All animals must rest, but do they really sleep as we know it? The answer to this question seems obvious. If an animal regularly
All animals must rest, but do they really sleep as we know it? The answer to this question seems obvious. If an animal regularly
admin
2011-05-29
63
问题
All animals must rest, but do they really sleep as we know it? The answer to this question seems obvious. If an animal regularly stops its activities and stays quiet and unmoving——if it looks as though it is sleeping——then why not simply assume that it is in fact sleeping? But how can observers be sure that an animal is sleeping?
They can watch the animal and notice whether its eyes are open or closed, whether it is active or lying quietly, and whether it responds to light or sound. These factors are important clues, but they often are not enough. Horses and cows, for example, rarely close their eyes, and fish and snakes cannot close them. Yet this does not necessarily mean that they do not sleep. Have you ever seen a cat dozing with an eye partly open? Even humans have occasionally been observed to sleep with one or both eyes partially open. Animals do not necessarily lie down to sleep either. Elephants, for example, often sleep standing up, with their tusks resting in the fork of a tree. Finally, while "sleeping" animals often seem unaware of changes in the sounds and light and other stimuli around them, that does not really prove they are sleeping either.
Observations of animal behavior alone cannot fully answer the question of whether or not animals sleep. The answers come from doing experiments in sleep laboratories, using a machine called the electroencephalograph (EEC). The machine is connected to animals and measures their brain signals, breathing, heartbeat, and muscle activity. The measurements are different when the animals appear to be sleeping than when they appear to be awake. Using the EEC, scientists have confirmed that all birds and mammals studied in laboratories do sleep. There is some evidence that reptiles, such as snakes and turtles, do not truly sleep, although they do have periods of rest each day, in which they are quiet and unmoving. They also have discovered that some animals, like chimpanzees, cats, and moles (who live underground), are good sleepers while others, like sheep, goats, and donkeys, are poor sleepers. Interestingly, the good sleepers are nearly all hunters with resting places that are safe from their enemies. Nearly all the poor sleepers are animals hunted by other animals: they must always be watching for enemies, even when they are resting.
Animals that are good sleepers ______.
选项
A、need to have a good sleep after they have exhausted themselves by getting rid of hunting animals
B、need to have a good sleep after they get tired from hunting other animals
C、are all mammals
D、almost always have a safe resting place
答案
D
解析
本题的依据句是第三段中的“Interestingly, the good... from their enemies”,从中可知,能睡觉的动物都是有安全休息地点的捕食者,所以D项正确。
转载请注明原文地址:https://kaotiyun.com/show/qW6O777K
0
考博英语
相关试题推荐
Lookatthelistbelow.Itshowsanumberofbusinesstrainingcourses.Forquestions6-10,decidewhichtrainingcourse(A-H)ea
Readthefollowingminutesofameeting.Aresentences16-22ontheoppositepage’Right’or’Wrong’?Ifthereisnotenough
Readthecommentsbelowfortheco-CEOmodel.Aresentences16-22ontheoppositepage’Right’or’Wrong’?Ifthereisnot
Readthearticlebelowaboutatakeoverbattlebetweenahotelchainandaninvestmentcompany.Aresentences16-22ontheopp
ItispossibleforstudentstoobtainadvanceddegreesinEnglishwhileknowinglittleornothingabouttraditionalscholarlyme
ItisnotoftenrealizedthatwomenheldahighplaceinsouthernEuropeansocietiesinthe10thand11thcenturies.Asawife,
Theprocessbymeansofwhichhumanbeingsarbitrarilymakecertainthingsstandforotherthingsmaybecalledthesymbolicpro
Theprocessbymeansofwhichhumanbeingsarbitrarilymakecertainthingsstandforotherthingsmaybecalledthesymbolicpro
Tosurviveintheintensetradecompetitionbetweencountries,wemust______thequalitiesandvarietiesofproductswemaketo
Atitsbest,anyprisonissounnaturalaformofsegregationfromnormallifethat--liketoo-lovingparentsandtoozealousre
随机试题
黄某因盗窃被处行政拘留15日,因赌博被处行政拘留15日。合并执行拘留时,最长不超过25日。
有关结肠痛下列哪项正确()
心肺复苏的“生存链”中,不包括
对病人自主与医生做主之间关系的最正确的理解是
甲公司是一家上市公司。2013年5月,中国证监会接到有关甲公司问题的举报,举报问题如下:(1)甲公司公布的2012年度年报显示的利润总额是人民币2000万元,实际是亏损人民币1300万元。为甲公司负责审计的乙会计师事务所的注册会计师张某和李某
A、 B、 C、 D、 C前一项除以后一项加1等于第三项,依此类推,空缺项为,故本题正确答案为C。
他说陶渊明的诗句有种真实、平凡而不可_________的美,且看:“_________远人村,依依墟里烟,狗吠深巷中,鸡鸣桑树颠……”填入画横线部分最恰当的一项是:
在科学认识中,意识的“超前反映”更为突出,这里称之为“超前反映”的意思主要是指()
十六进制数CDH对应的十进制数是
Often,capriciousnessisthereasongivenfordoingnothing.Flexibleworkingisanaddedopportunitytoallowstaffattheshar
最新回复
(
0
)