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
A、To tell the crab what time it is. B、To protect the crab from the sunlight and enemies. C、To keep the crab warm. D、To be of no
A、To tell the crab what time it is. B、To protect the crab from the sunlight and enemies. C、To keep the crab warm. D、To be of no
admin
2010-05-09
11
问题
Thefiddler crab ( 招潮蟹) is a living clock. It indicates the time of day by the color of its skin, which is dark by day and pale by night. The crab’s changing skin color follows a regular 24-hour cycle that exactly matches the daily rhythm of the sun.
Does the crab actually keep time, or does its skin simply respond to the sun’s rays, changing color according to the amount of light that strikes it? To find out, biologists kept crabs in a dark room for two months. Even without daylight, the crabs’skin color continued to change precisely on schedule.
This characteristic probably evolved in response to the rhythm of the sun, to help protect the crab from sunlight and enemies. After millions of years it has become completely regulated inside the living body of the crab.
The biologists noticed that once each day the color of the fiddler crab is especially dark, and that each day this occurs 50 minutes later than on the day before. From this they discovered that each crab follows not only the rhythm of the sun but also that of the tides. The crab’s period of greatest darkening is precisely the time of low tide on the beach where it is caught.
选项
A、To tell the crab what time it is.
B、To protect the crab from the sunlight and enemies.
C、To keep the crab warm.
D、To be of no real use.
答案
B
解析
事实细节题 文中谈到招潮蟹的肤色随时间变化是为了保护自己避开阳光和敌人的伤害。
转载请注明原文地址:https://jikaoti.com/ti/i7YMFFFM
0
大学英语六级
相关试题推荐
A、Peopleareexpectedtocomeatsix.B、Aformalpartywillbeheld.C、Itwillbeapartyforrelaxation.D、Thereisnoneedto
Thepassagemainlydealswithhowforeignteachersshouldtrytogetmorepaidwhentheyintendtoworkforaschool.Theexper
A、Theyarethoroughlywetontheirwaytotheconcert.B、Theymissedtheconcertbecauseoftherain.C、Theywilldryofftheir
Dafterinterviewingbecomecommonpractice【S1】______intheUnitedStates,Americanjournalistswereteaching
A、Thosewhoknowhowtoprogramcomputers.B、Thosewhogetspecialaidfromtheirteachers.C、Thosewhoareveryhardworking.D、
Somepeoplehavetheage-olddesiretoputthejokeonothers.Dihydrogenmonoxideisaverydangerouschemical,whichisoften
A、Presentanewtheorytotheclass.B、Readmorethanonearticle.C、Readthebookmorethoroughly.D、Writeabetterarticlefor
A、Hurrytotheconference.B、Skiptheconference.C、Takethesubway.D、Takeabus.D
A、Shewilltakesubway.B、Shewillhurrytotheconference.C、Shewillskiptheconferenceandgosightseeing.D、Shewilltakea
BluetoothWhenyouusecomputers,entertainmentsystemsortelephones,thevariouspiecesandpartsofthesystemsmakeupa
随机试题
在Word中插入图片的环绕方式默认为()。
关于侵占罪的认定(不考虑数额),下列哪些选项是错误的?()
两个或两个以上的对等经济实体,为了共同的战略目标,通过各种协议而结成的利益共享、风险共担、要素水平式双向或多向流动的松散型网络组织体,称为()。
应收账款账户借方登记的是应收款项的增加数。()
Hewrotetosay______(他们终究还是不能给我一份工作).
中国行政管理的主要特征包括()。
2,3,7,(),121,721。
设齐次方程组(Ⅰ)有一个基础解系β=(b11,b12,…,b1×2n)T,β2=(b21,b22,…,b2×2n)T,…,βn=(bn1,bn2,…,bn×2n)T.证明A的行向量组是齐次方程组(Ⅱ)的通解.
LanguagesinAmericaTheUnitedStatesis【T1】______anEnglishspeakingcountry.The【T2】______ofthepopulationspeaksEngli
GratefulPeopleAreHappierandHealthierA)Itturnsoutthatgivingthanksisgoodforyourhealth.Agrowingbodyofre
最新回复
(
0
)