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
65
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.
The statement "Horses and cows, for example, rarely close their eyes" aims to show that ______.
选项
A、these animals rarely need any rest
B、they almost always keep alert to danger
C、they often stay awake
D、their eyes are rarely closed even when they are asleep
答案
D
解析
本题可参照第二段,即马和牛很少闭上眼睛,但这并不能说明它们不睡觉。事实上它们睡觉的时候眼睛经常是睁开的。据此可知D项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/YW6O777K
0
考博英语
相关试题推荐
TheLondonCentreForyourmeeting,productlaunch,specialeventPurpose-builtroomsLatestpresentationtechnologyFirst-class
•Readthearticlebelowaboutasuccessfulbusinessman.•Foreachquestion(23-28)belowthearticle,choosethecorrectansw
MotivatingYourRetailSalesStaffinSlowTimesAlwaysgetinputfromyourstaffatthesemeetingsandhavesomefunwitha
Readthearticlebelowaboutasuccessfulbanker.Aresentences16-22ontheoppositepage’Right’or’Wrong’?Ifthereis
Thoughthisapparatusisexpensive,thepatientagreedtouseitaftertheoperationbecauseitcould______thepain.
Theprocessbymeansofwhichhumanbeingsarbitrarilymakecertainthingsstandforotherthingsmaybecalledthesymbolicpro
Thedoctor’s______isthatshe’llsoonbeasgoodasnewifshetakesinsulinandwatchesherdiet.
Herremarks______acompletedisregardforhumanrights.
Tobroadentheirvotingappealinthepresidentialelectionof1796,theFederalistsselectedThomasPinckney,aleadingSouthC
Manywell-educatedpeopledon’tbelievethat______willendangerfreedomofspeech.
随机试题
电子书阅读平台定期从内容资源库获取图书资源的下载方式是()。
在Excel中,选中活动工作表的一个单元格后执行“编辑”菜单中“清除”中的子命令,可以__。
可提高婴儿出生后局部免疫屏障的是
A、紧密结合临床B、内容广泛多样C、更新传递快速D、做到去伪存真E、提高药学水平冷静分析识别各种信息,开展EBDI是为了使药物信息()
根据《钢结构工程施工质量验收规范》规定,钢结构一级、二级焊缝不得有()等缺陷。
根据政府预算编制依据的内容和方法,可将政府预算分为()。
()被誉为“音乐化石”。
班会的特点主要有集体性、针对性和()。
如果想查广东以前各市、县发生的大事,从2008年起查,要用哪种检索方法?()
某用户在WWW浏览器地址栏内键入了一个URL:http://www.dlut.edu.cn/index.htm,其中“index.htm”代表_______。
最新回复
(
0
)