首页
登录
职称英语
Why don’t birds get lost on their long flights from one place to another? Sci
Why don’t birds get lost on their long flights from one place to another? Sci
游客
2025-03-15
30
管理
问题
Why don’t birds get lost on their long flights from one place to another? Scientists have been puzzled over this question for many years. Now they’re beginning to fill in the blanks.
Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly by night? (37) Tests with artificial stars have proved that certain night-flying birds are able to follow the stars in their long-distance flights.
A dove had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight.
The stars are apparently their principal means of navigation. When the stars are hidden by clouds, they seemingly find their way by such landmarks as mountain ranges, coast lines, and river courses. But when it’s too dark to see these, the doves circle helplessly, unable to find their way. [br] In total darkness, doves______.
选项
A、use landmarks to find their way
B、don’t know which way to fly
C、make their return flight
D、wait for the stars to appear
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3998732.html
相关试题推荐
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
Whydon’tbirdsgetlostontheirlongflightsfromoneplacetoanother?Sc
SpeakerA:Itseemsthatwe’llhaveanotherfinedaytomorrow.Let’sgotothes
AUniversityofVersaillesstudentmaytakecourseworkatanotherinstituti
Ifyouwillbuyoneboxattheregularprice,youwouldreceiveanotheroneatn
Itusuallytakesmuchlesstimetoflyfromonecountrytoanotherthantravelin
Thefisherman,______poor,couldnotbuyanotherboat.A、isB、wasC、beingD、been
随机试题
ItwasabeautifulsummerdayandIwastakingawalkinthedowntownareao
Formostpeoplewhohavesleepingtroubles,whichofthefollowingisthemostu
如果重组病毒携带了控制细胞生长分裂的原癌基圈,使其以导常高的水平表达或经突变失去
某汽车维修公司有部门、员工和顾客等实体,各实体对应的关系模式如下:部门(部门代码
一般而言,风险偏好型客户会倾向于选择()。 Ⅰ垃圾债券 Ⅱ股指期货 Ⅲ投
某患者,男,70岁,大便秘结,小便清长,腰膝酸软,头目眩晕,舌淡苔白,脉沉迟。治
请画出线路电流保护回路图。
按照美国学者古德莱德的课程层次理论,教师在课堂教学中具体实施的课程属于(
简述现代企业人力资源管理各个历史发展阶段的特点。
引起尖锐湿疣的病原体是( )。A.人免疫缺陷病毒 B.人乳头瘤病毒 C.E
最新回复
(
0
)