首页
登录
职称英语
Why don’t birds get lost on their long flights from one place to another? Scient
Why don’t birds get lost on their long flights from one place to another? Scient
游客
2024-07-19
34
管理
问题
Why don’t birds get lost on their long flights from one place to another? Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blares.
Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly at night? 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.
But the stars are apparently their principal means of navigation. When the stars are hidden by clouds, they apparently 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
B、don’t know which way to fly
C、fly back home
D、wait for the stars to appear
答案
B
解析
见本文最后一句:“But when it’s too dark to see these, the doves circle helplessly unable to find their way. ”
转载请注明原文地址:https://tihaiku.com/zcyy/3683628.html
相关试题推荐
NotonlyIbutalsoJaneandMaryaretiredofhavingonemeetingafteranother.
Qantas(广达斯航空公司)hasmoreflightstomoreplacesthananyotherAustralianairli
Scientistsaretryingtomakethedesertsintogoodlandagain.Theywantto
Scientistshavediscoveredthatteaisgoodforus.Ittastesgoodanditis
Scientistshavediscoveredthatteaisgoodforus.Ittastesgoodanditis
ThereisanothersalethisChristmasseason.Withtheslidingsoundofcash
Qantas(广达斯航空公司)hasmoreflightstomoreplacesthananyotherAustralianair-l
Scientistshavebeentryingtocomeupwithbiologicalexplanationsforthediff
Scientistsandexpertshaveprovedthatthepatternofahumanbeing’sfingersk
Scientistsandexpertshaveprovedthatthepatternofahumanbeing’sfingersk
随机试题
[originaltext]M:Hi,I’mfromtheStudents’Union.We’redoingasurveyofstud
[originaltext]M:Honey,thebasketballgameisabouttostart.Andcouldyoubr
29岁男性患者,左上前牙不慎撞断1天,冷热刺激痛,要求修复。口腔检查示左上2外伤
治疗口舌生疮、小便短赤首选A.茯苓 B.滑石 C.竹叶 D.芦根 E.浮
为保护投资者权益,证券公司应在代销金融产品前进行必要的( )。A.委托人资格审
共用题干 王先生夫妇今年都刚过40岁,年收入20万元左右,打算60岁退休,估计
交流单芯、分相电缆穿过金属护板时,金属护板不应形成()。闭合磁路$;$接地$
资产负债表中“固定资产”项目应根据“固定资产”账户余额直接填列()。
对于这种观点:“t检验适用于样本容量小于30的情况,而大样本才适合使用z检验。”
关于劳动合同试用期问题,说法正确的是( )。A.劳动合同期限三个月以上不满一年
最新回复
(
0
)