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
2020-03-30
59
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 un-moving—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/fnTO777K
0
考博英语
相关试题推荐
Inourcontemporaryculture,theprospectofcommunicatingwith—orevenlookingat—astrangerisvirtuallyunbearable.Everyone
ManycountrieswillnotallowcigaretteadvertisingintheirnewspapersoronTVespeciallysincetheadvertisementsareusually
ManycountrieswillnotallowcigaretteadvertisingintheirnewspapersoronTVespeciallysincetheadvertisementsareusually
Allanimalsmustrest,butdotheyreallysleepasweknowit?Theanswertothisquestionseemsobvious.Ifananimalregularly
Humanbeingsareanimals.Webreathe,eatanddigest,andreproducethesamelife【C1】______commontoallanimals.Inabiologica
Thepolicefoundsomestolen______hiddeninthethief’shouse.
(北京航空航天大学2013年试题)Mostworthwhilecareersrequiresomekindofspecializedtraining.Ideally,therefore,thechoiceofan【C1】
(北京航空航天大学2013年试题)Mostworthwhilecareersrequiresomekindofspecializedtraining.Ideally,therefore,thechoiceofan【C1】
Alltheroomsonthesecondfloorhavenicely______carpets,whichareincludedinthepriceofthehouse.
随机试题
用K分度热电偶测温时,热端温度t时测得热电势Ek
HankViscardiwasbornwithoutlegs.Hehadnolegsbutstumps(残肢)thatcouldbefittedwithakindofspecialboots.Peoplesta
微小病变肾病的主要病理改变是()(2007年)
应用安全、疗效确切、质量稳定、应用方便积极稳妥、分步实施、注重实效、不断完善,加强处方药的监督管理,规范非处方药的监督管理
背景某房地产开发公司投资建造一座高档写字楼,钢筋混凝土结构,设计项目已明确,功能布局及工程范围都已确定。业主为减少建设周期,尽快获得投资收益,施工图设计未完成时就进行了招标。(1)招标工作中发生了以下事件:①招标文件规定本地区
云南白药()
为防止流于形式的复核,对资产评估报告必须建立起()的制度。
科学家们观测到南极上空在春天到初夏期间会有臭氧耗损,臭氧层变薄的情形,俗称臭氧空洞;而北极上空的臭氧空洞则不明显。这是因为南极地区的冬天远较北极地区寒冷所致。南极的最暖月约一300C,最冷月一600C,而北极最暖月00C,最冷月一400C。南极臭氧层空洞一
设方程x+z=yf(x2一z2)(其啊可微)确定了z=z(x,y),则().
Let’sfaceit.Gardeningfanaticslikenothingbetterthantohavetheirhandsstuckinthesoilortobetrimming,pruning,or
最新回复
(
0
)