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
考研
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
2014-06-13
104
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.
According to the author, all animals______.
选项
A、spend some time resting
B、close their eyes when sleeping
C、are good sleepers
D、are poor sleepers
答案
A
解析
答案A(all animals must spend.some time resting)跟第一段的首句A11 animals must rest意思相同。
转载请注明原文地址:https://kaotiyun.com/show/8aO4777K
0
考研英语一
相关试题推荐
ReadthefollowingtextcarefullyandthentranslatetheunderlinedsegmentsintoChinese.Yourtranslationshouldbewrittencl
Theword"interest"inthefirstparagraphmostprobablymeansAccordingtothetext,theauthorseemstobe
Accordingtotheauthor,theAmericaneconomicsituationis______.Theofficialstatisticsonproductivitygrowth______.
Cats,accordingtotheauthor,______.Wecaninferfromthepassagethattheauthor______.
Howdoestheauthorthinkofhimself?Themostviciouslawyersarethosewho
Intheeyesofthewriter,bankfailuresintheearly1930s______.Accordingtothetext,whatsurprisesthewriteristhatco
Nowa.dayspeoplearelikelytofeelthatthey______.Today,dyingyoungis______.
Thefindingiscontrarytothecommonbeliefthatallpeoplearemotivatedtoalleviatenegativemoods,accordingtoJonathonBr
ThatLouiseNevelsonisbelievedbymanycriticstobethegreatesttwentieth-centurysculptorisallthemoreremarkablebecaus
Lowlevelsofliteracyandnumeracyhaveadamagingimpactonalmosteveryaspectofadults,accordingtoasurveypublishedyes
随机试题
图示饮片为川木通的是
简述犯罪的含义及犯罪构成。
患者,女,15岁。13岁月经初潮,现月经周期无规律性,下列说法不正确的是
下列哪种纤维素衍生物不溶于水,其醇液可用作对水敏感药物的黏合剂( )。
与药物溶解度无关的因素是
患者,男性,69岁,情绪激动后突感剧烈压榨性胸痛、呕吐伴窒息感2小时入院。心率110/分,血压82/60mmHg,心电图示V1~V4导联ST段弓背抬高,心律失常。护士为患者采取的护理措施应除外
下列关于减刑的说法中,符合《刑法》规定的是()。
以下煤炭资源中征收资源税的有()。
高油价时代,如何节油成为车主们关注的焦点,于是各种节能产品__________,汽油清净剂、节油贴、节油丸、省油精等等__________。填入划横线部分最恰当的一项是:
如果邢经理首先赴安徽省调研,则关于他的行程,可以确定以下哪项?
最新回复
(
0
)