首页
登录
职称英语
[originaltext] Many egglaying animals merely lay their eggs and leave. With
[originaltext] Many egglaying animals merely lay their eggs and leave. With
游客
2023-07-12
67
管理
问题
Many egglaying animals merely lay their eggs and leave. With turtles for instance, the eggs hatch on their own. The current theory about birds is that the earliest birds did just that, when they were coldblooded creatures living in warm places. However when they became warmblooded creatures living in cold places they had to remain on top of the eggs to keep them warm. This process we call incubation. For this they needed a place, a nest very likely the first nests were just primitive depressions scraped into the ground. Even now many species still lay eggs in this sort of crude nest. In fact, every spring a mother killdeer lays her eggs in scene pebbles along the edged the parking lot just outside this building. Primitive nests on the ground were fine for some birds but others began to elevate their nests onto Branches, perhaps to avoid predators. These early elevated nests were probably loose platforms of sticks and twigs, the types still built by ospreys and mostarians today. The latest evolutionary development in nests the most re cent version, so to speak, is the cupshaped nest. This is the one we regard today as the typical bird’s nest, you know, like a robin’s nest.
选项
A、In order to elevate their nests.
B、In order to live more comfortably.
C、In order to avoid predators.
D、In order to make incubation easier.
答案
C
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2830017.html
相关试题推荐
[originaltext]Arecentfilm,TheCodsMustBeCrazy,describedthesocialc
[originaltext]TheCivilWarcameaboutasaresultofmanydifferencesbetw
[originaltext]TheCivilWarcameaboutasaresultofmanydifferencesbetw
[originaltext]ColumbussailedfromSpaininSeptember1492,lookingforgold.
[originaltext]ColumbussailedfromSpaininSeptember1492,lookingforgold.
[originaltext]M:Hello.Ineedtotalkwithsomeoneaboutmydriver’slicense.
[originaltext]M:Hello.Ineedtotalkwithsomeoneaboutmydriver’slicense.
[originaltext]M:Excuseme.Haveyoubeenwaitinglong?W:Abouttenminutes.M
[originaltext]M:Linda,whydoyouneedmynotes?IrememberseeingyouinProf
[originaltext]M:Linda,whydoyouneedmynotes?IrememberseeingyouinProf
随机试题
Insuranceisthesharingof【C1】________Nearlyeveryoneisexposed【C2】_______
下列不属于气体灭火系统的系统功能验收要求的是()。A.系统功能验收时,应对
IPv4报文分片和重组分别发生在()。A.源端和目的端 B.需要分片的中间路由
患者,女性,22岁。未婚处女,13岁月经初潮,周期基本规律。近半年来月经期延长,
A.肉类食品 B.两者皆有 C.两者皆无 D.海产品可引起沙门菌属食物中毒
巴豆入丸散剂的剂量是每次A.0.01~0.03g B.0.5~1g C.
Thechangeinthatvillagewasmiraculou
关于毒性药品的销毁处理说法不正确的是A:对不可供药用的毒性药品,经单位领导审核,
良性肿瘤的最显著的特点是A.不转移 B.生长缓慢 C.不浸润周围组织 D.
生态环境影响分析主要对( )进行分析。A.自然环境状况 B.生态环境状况 C
最新回复
(
0
)