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
51
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、They began to lay eggs.
B、They changed their migration patterns.
C、Their flying ability improved greatly.
D、They become warmblooded.
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2830015.html
相关试题推荐
[originaltext]TheLondon’sDistrictCourtdismissedthedamagesuitbrought
[originaltext]TheLondon’sDistrictCourtdismissedthedamagesuitbrought
[originaltext]TheLondon’sDistrictCourtdismissedthedamagesuitbrought
[originaltext]WhenIfirstwenttoLondonasastudent,Isataloneduring
[originaltext]Thedaystartedbadly,IwokeuplatebecauseIforgotabout
[originaltext]M:Hello,LiLi.Comeonin.How’veyoubeenkeepingrecently?W:
[originaltext]M:Hello,LiLi.Comeonin.How’veyoubeenkeepingrecently?W:
[originaltext]M:Hello,LiLi.Comeonin.How’veyoubeenkeepingrecently?W:
[originaltext]M:Areyoubusytonight?Iwanttoaskyoutogotothemovies.W
[originaltext]M:Areyoubusytonight?Iwanttoaskyoutogotothemovies.W
随机试题
Whatdoesthewomanmean?[br][originaltext]M:CanIhavetheearphonechanged
Anewstudysuggeststhatthecloseinterspeciesbondthatexistsbetweenhu
德国一位女牙医助理马里翁在一次车祸中受重伤,送到医院后被判定为脑死亡,后来的全面
以下除哪项外均是木香的主治病证A.三焦气滞 B.肺气阻滞 C.肝胆气郁 D
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性:
中国电脑行业领导者某集团不仅固守现有的商品和业务领域,还将业务领域扩展到一些有潜
对于丝裂霉素注意事项的描述,错误的是A.长期应用可抑制卵巢及睾丸功能,造成闭经或
乙是A市的建材经销商,因资金周转困难,便从A市甲处借了50万元人民币,购买
薪酬成本控制的方法有( )。A.控制雇佣量 B.控制基本薪酬 C.控制差
下列乙肝病毒标记物中反映HBV有活动性复制和传染性的是A.表面抗体(抗-HBs)
最新回复
(
0
)