首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、They began to lay eggs. B、They changed their migration patterns. C、Their flying ability improved greatly. D、They become warmbl
A、They began to lay eggs. B、They changed their migration patterns. C、Their flying ability improved greatly. D、They become warmbl
admin
2013-06-17
65
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://kaotiyun.com/show/hDM7777K
0
大学英语四级
相关试题推荐
Onlinebillpaycanhelpyoumanageyourbillswithouthavingtoworryaboutpaperbillsandchecks.【B1】______youhaveonlineb
A、Nickcan’tgoonstudyingbecausehehastoworkinasteelplant.B、Nickhasearnedenoughmoneyforhissenioryear.C、Nick
Thestudyofsignlanguageisthoughttobe______.MosteducatorsobjectedtoStokoe’sideabecausetheythought______.
A、TheyarethemostattractivewomeninBritain.B、Theyarethemostpopularfilmstars.C、Theyarethefirstwomennewsannounc
A、Atapublishinghouse.B、Atabookstore.C、Inareadingroom.D、InProf.Jordan’soffice.B
Thefridgeisconsideredanecessity.Ithasbeensosincethe1960swhenpackagedfoodfirstappearedwiththelabel:"storein
A、HowtheSpiceGirlsbecamesuccessful.B、HowtheSpiceGirlsrenamedthegroup.C、HowthemanagerfoundtheSpiceGirls.D、Why
ShouldSugarBeRegulatedlikeAlcoholandTobacco?Sugarposesenoughhealthrisksthatitshouldbeconsideredacontrolle
A、Thelocalambulanceandfiremenimmediatelycametotherescue.B、Allthepassengerswerekilled.C、Additionalhelpwasunnece
随机试题
简单商品经济的基本矛盾是()
男性,50岁,哮喘史7年。严重发作持续已两天,痰黏稠、尿少。查体:呼吸困难,烦躁不安,发绀,心率128次/分,双肺呼吸音低,少许哮鸣音。下列治疗哪项是错误的
孕妇,29岁。分娩过程中,出现不协调性子宫收缩乏力,正确的处理是
战争开始会使交战国间的法律关系发生重大变化,产生一系列的法律后果,以下哪一项不属于产生的法律后果?
票据丢失后,可以采取的补救措施主要有()。
某演唱会定于晚上7点30分在鸟巢举行,根据安保工作要求,在人口要求观众需经过安检才可入场。观众甲在接受安检时,安检器发生鸣叫,执勤民警李某要求其打开随身携带的包进行检查,甲以包内物品涉及个人隐私为由拒绝接受安检。在李某多次劝说下,甲仍不同意并同李某发生争吵
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。
flashquit
设一棵满二叉树共有15个结点,则在该满二叉树中的叶子结点数为()。
The______inJanet’scharacterhashinderedherfromadvancementinhercareer.
最新回复
(
0
)