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、They use a map and the memory of location. B、They use the sun and the stars. C、They use a map and the earth’s magnetic field.
A、They use a map and the memory of location. B、They use the sun and the stars. C、They use a map and the earth’s magnetic field.
admin
2009-04-23
78
问题
How do the birds manage to find their way? There seems to be no single answer: they use many methods. Some we are beginning to understand; and there may be some that depend on abilities we have not yet suspected. Many birds certainly follow major geographical features. Migrants follow recognized land, fly over sea and arrive at their summer homes.
But all birds cannot use such straightforward methods. An Arctic sea bird, for example, has to fly at least 3,000 kilometers across the Antarctic Ocean with no land to guide it. We know that some birds flying at night, navigate by the stars for on cloudy nights they tend to get lost.
Day-flying birds may use the sun. If they are to do so, they must have a precise sense of time. Still others appear to be able to use the earth’s magnetic field as a guide. So it seems that many migrating birds must carry in their brains a clock, a compass and the memory of a map.
选项
A、They use a map and the memory of location.
B、They use the sun and the stars.
C、They use a map and the earth’s magnetic field.
D、They have precise sense of time or may use the earth’s magnetic field.
答案
D
解析
How do day-flying birds find their way?
转载请注明原文地址:https://kaotiyun.com/show/OOR7777K
0
大学英语四级
相关试题推荐
期货投资基金的投资策略包括()。
A、Treescanprotectcropsfromwind.B、Cropsgrowingontreeshelpfeedpeople.C、Cropsandtreescannotgrowinonefield.D、Tr
A、Heoftenborrowsmoneyfromothers.B、Hehasjustreceivedhismonthlypay.C、Hecan’tpayoffhiscreditcards.D、Hehaskept
A、Forestscan’tbeusedas"carbonsinks".B、Carboncan’tbestoredinrainforest.C、Compensationcan’tbedistributed.D、Global
Forthispart,youareallowed30minutestowriteanessaybasedonthefollowingdrawing.Inyouressay,youshouldfirstdesc
A、Hehastospendalongtimefindingtheinformationhewants.B、Hedoesn’tknowanyusefulwebsites.C、Hedoesn’tknowhowto
A、Thegroupplacedinbluelight.B、Thegroupdrinkingthemostwater.C、Thegroupplacedinredlight.D、Thegroupeatingthel
A、Byreadingherpolishedessay.B、Byproofreadingherfirstdraft.C、Bybringinghersomereferencebooks.D、Byexamininghero
A、Hediedinatrafficaccident.B、Hefellillandpassedawayunexpectedly.C、Hestayedinthehospitalforawhile.D、Hehada
A、Themanisfondoftraveling.B、Thewomanisaphotographer.C、Thewomantookalotofpicturesatthecontest.D、Themanadmi
随机试题
黄芩、黄连、黄柏的共同主治病证是
维系蛋白质二级结构稳定的主要化学键是
常用来制作建筑用给排水管及卫生洁具的塑料是:[2011-008]
到岸价(CIF价)是指进口货物运抵我国进口口岸交货的价格,它包括()、()。
立井井筒表土段采用冻结法施工时,其水文观测孔应该布置在()
下列会计档案中,保管期限为5年的是()。
下列有关前后任注册会计师沟通的说法中,错误的是()。
()是指在某一既定时期一个国家内生产的全部社会最终产品和劳务价值的总和,包括消费、投资、政府购买和净出口四个部分。
国家机关对新录用公务员应当在试用期内进行()。
某厂三台机器同时出了故障。修复这3台机器花费的时间分别为5分钟,6分钟,8分钟,每台机器停产1分钟给工厂造成经济损失100元,维修组依次维修了这3台机器,合理安排维修顺序能减少经济损失。经济损失最小为()元。
最新回复
(
0
)