首页
登录
职称英语
[originaltext] The fiddler crab is a living clock. It indicates the time of
[originaltext] The fiddler crab is a living clock. It indicates the time of
游客
2023-09-12
43
管理
问题
The fiddler crab is a living clock. It indicates the time of the 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 twenty-four 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 crab’s skin color continued to change precisely on schedule.
The 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 fiddle crab is especially dark, and that each day this occurs fifty 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 was caught.
选项
A、By the work of biologists.
B、In the process of evolution.
C、Over millions of years.
D、Both A and B
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3008232.html
相关试题推荐
[originaltext]Architectureistobuildingasliteratureistotheprintedwo
[originaltext]Scientistsclaimthatairpollutioncausesadeclineinthewo
[originaltext]Scientistsclaimthatairpollutioncausesadeclineinthewo
[originaltext]W:Oh,Rex,Ihavebeenlookingforyouforhours.Wherehaveyou
[originaltext]W:Oh,Rex,Ihavebeenlookingforyouforhours.Wherehaveyou
[originaltext]AnenvironmentalgroupcalledtheFoodCommissionisunhappya
[originaltext]EveryoneknowsabouttheRoyalCanadianMountedPolice,but(2
[originaltext]EveryoneknowsabouttheRoyalCanadianMountedPolice,but(2
[originaltext]EveryoneknowsabouttheRoyalCanadianMountedPolice,but(2
[originaltext]Notlongagoitwasassumedthatthedangersmanwouldmeetin
随机试题
PASSAGETWO[br]WhatdidTitzeplantofindoutaboutastronauts’urinepattern
Unlikeothercountries,thepoliceintheUKdonotcarryguns.Somethinkt
"OrganicArchitecture"Oneofthemoststrikingpers
60岁患者,恶液质,嗜睡,无突眼,甲状腺肿大不明显,有结节,心率100次/分,血
用代用法中的不变水量法测定水泥标准稠度用水量时,当试锥下沉深度小于15mm时,应
Thechangeinthatvillagewasmiraculou
为防治社会生活噪声污染,制定了《中华人民共和国环境噪声污染防治法》,下列不符合规
(2017年11月)福利的()容易让员工低估企业的人工成本。A.稳定性 B
A.40 B.30 C.10 D.5
关于建筑施工企业安全生产许可证的说法,正确的是( )。A.没有施工许可证,不得
最新回复
(
0
)