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
58
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
•ReadthearticlebelowabouttheASTA.•Inmostofthelines34-45thereiso
Doyouknowinsurance(保险)?Buyinginsuranceisa【C1】______bywhichpeopleca
[originaltext]W:Youwereabsentfromworkyesterday,Brown.M:I’mterriblys
当医务人员的利益与医学界、服务对象以及整个社会的利益发生冲突而不能两全的时候,医
A.自始至终影响 B.归根结底妨碍 C.无庸讳言干扰 D.理所当然
洛伐他汀INN命名中含有的词干是A.dan B.vastatin C.azo
2020年上半年,我国农产品进出口总额达1159.0亿美元。农产品进口额为807
在一项实验研究中,研究者将受试者随机分为A、B两个小组,A组接受法律培训,B组不
重大事故隐患管理制度的要点有()A:重大事故隐患分类 B:重大事故隐患报告
导致慢性阻塞性肺气肿发病的最主要因素是A.感染 B.吸烟 C.大气污染 D
最新回复
(
0
)