首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
Passage 1 Plants and animals that have been studied carefully seem to have b...
Passage 1 Plants and animals that have been studied carefully seem to have b...
admin
2020-12-24
10
问题
Passage 1
Plants and animals that have been studied carefully seem to have built-in clocks. These biological clocks, as they are called, usually are not quite exact in measuring time. However, they work pretty well because they are "reset" each day, when the sun comes up.
Do pigeons use their biological clocks to help them find directions from the sun? We can keep pigeons in a room lit only by lamps. And we can program the lighting to produce artificial "days",different from the day outside. After a while we have shifted their clocks. Now we take them far away from home and let them go on a sunny day. Most of thegn start out as if they know just which way to go, but choose a wrong direction. They have picked a direction that would be correct for the position of the sun and the time of day according to their shifted clocks.
It is known and experimented that homing pigeons can tell directions by the sun. But what happens when the sky is darkly overcast by clouds and no one can see where the sun is? Then the pigeons still find their way home. The salne experiment has been repeated many times on sunny days and the result was always the same. But on very overcast days clock-shifted pigeons are just as good as normal pigeons in starting out in the right directions. So it seems that pigeons also have some extra sense of direction to use when they cannot see the sun.
Naturally, people have wondered whether pigeons might have a built-in compass—something that would tell them about the directions of the earth's magnetic field. One way to test that idea would be to see if a pigeon's sense of direction can be fooled by a magnet attached to its back.
With a strong magnet close by, a compass can no longer tell direction.
To test the idea, a group of ten pigeons had strong little magnet bars attached to their backs.
Another group carried brass bars instead which were not magnetic. In a number of experiments,both groups were taken away from home and let go. On sunny days none of the magnet-pigeons was fooled. They were just as good as the brass-pigeons in starting out in the right direction toward home. On cloudy, overcast days, however, with no sun the brass-pigeons chose the right direction,but the magnet-pigeons were in trouble. They later started out in different directions and acted completely lost.
How can people shift pigeons' biological clocks?
查看材料
选项
A.By training them when they are young.
B.By minor and harmless operations.
C.By taking them really far away from home.
D.By keeping them in artificial days.
答案
D
解析
根据第二段中“And we can program the lighting to produce artificial‘days’,different from the day outside.After a while we have shifted their clocks."可以得知D项正确。
转载请注明原文地址:https://ti.zuoweng.com/ti/XTT8KKKQ
相关试题推荐
Passage2 Americanstodaydon′tplaceaveryhighvalueonintellect.Ourhe...
Passage2 Americanstodaydon′tplaceaveryhighvalueonintellect.Ourhe...
Passage2 Americansdon’tliketolosewars.Ofcourse,alotdependsonhowy...
Passage2 Americansdon’tliketolosewars.Ofcourse,alotdependsonhowy...
Passage2 Americansdon’tliketolosewars.Ofcourse,alotdependsonhowy...
Passage2 Americansdon’tliketolosewars.Ofcourse,alotdependsonhowy...
Passage2 Ofallthecomponentsofagoodnight′ssleep,dreamsseemtobe...
Passage2 Ofallthecomponentsofagoodnight′ssleep,dreamsseemtobe...
Passage2 ForcenturiesinSpainandLatinAmerica,headinghomeforluncha...
Passage2 ForcenturiesinSpainandLatinAmerica,headinghomeforluncha...
随机试题
修正久期是在麦考利久期概念的基础上发展而来的,用于表示( )变化引起的债券价格
(39-40题共用备选答案) A.清热燥湿 B.清热燥湿,泻火解毒 C.清
2017年7月,某制造业企业转让一项专利权开具增值税专用发票上注明的价款为100
“八五粉”与“八一粉”相比,丢失了很多维生素、纤维素和矿物质。( )
乖离率BIAS指标的应用法则是( )。
影响问题解决的重要因素是()、()、()和()。
仰卧位时,吸入性肺脓肿好发于A.上叶后段或下叶背段B.下叶后基底段C.右上叶前段或后段D.右下叶后基底段E.肺尖部
【背景资料】 某安装公司承接一商务楼(地上30层、地下2层)的电梯安装工程,工程有32层32站曳引式电梯8台,工期为90天,开工时间为3月18日,其中6...
关于建设工程监理,下列选项中正确的是()。A、监理应当遵守法律法规、强制性标准,遵循守法,公平、独立、诚信的原则,认真履行监理职责B、监理工程师应当按照
下列关于各种产品成本计算方法的表述中,正确的有()。A.品种法既不要求按产品批别计算成本,也不要求按生产步骤计算成本B.分批法适用于单件小批单步骤生产和管理