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
How does a whale keep itself warm?
How does a whale keep itself warm?
admin
2016-11-17
25
问题
How does a whale keep itself warm?
Millions of years ago, whales lived on land and walked on four legs. Today, whales still have small bones that are the remains of their hind legs, but these bones can only be seen on the inside of the whale. No one knows why whales left the land to live in the water.
However, scientists can imagine that when the whales changed their environment, their bodies underwent a change—taking on a more fish-like appearance. This new form offered less resistance to the water, enabling the whales to swim faster.
Despite their fish like form, whales are not fish. A whale will drown, just as a man will, if it stays under water too long. When a whale is under water, it closes its nostrils tightly and holds its breath. The air in its lungs becomes very hot and full of water vapor. When the whale rises to the surface and exhales, its hot breath produces a column of water vapor that rises high in the air. A man produces the same effect when he exhales warm air on a cold morning.
Whales are classified as mammals because they bear their young, rather than laying eggs, and because the mother whales give the babies milk. Like other mammals, whales have warm blood. Their blood stays at the same temperature, even when they move from hot to cold water. They keep warm in cold water because they have a thick layer of fat just under their skins. This fat is called blubber, and it is thicker on whales that spend their lives in cold water. Almost all land mammals, except man, have hair on their bodies to keep them warm, but whales, which have very few hairs, are kept warm by their fat.
选项
A、By its thick layer of fat under its skin.
B、By moving frequently in the water.
C、By adjusting its blood temperature.
D、By taking in hot air.
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/AVRd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
Studythefollowingtablecarefullyandwriteanessaybasedontheoutlinebelow:(1)Describethetable.(2)Possible
Thestudyofsocialscienceismorethanthestudyoftheindividualsocialsciences.Althoughitistruethattobeagoodsoci
Theconceptofpersonalchoiceinrelationtohealthbehaviorsisanimportantone.Anestimated90percentofallillnessesmay
Inafewweeks,nighschoolstudentsfacetheprospectoftakingthemuch-publicizednewSATReasoningTest,whichforthefirst
Ifyouintendusinghumorinyourtalktomakepeoplesmile,youmustknowhowtoidentifysharedexperiencesandproblems.Your
Whatarethespeakersmainlydiscussing?
Howdoesawhalekeepitselfwarm?
collision
OnthenorthbankoftheOhioRiversitsEvansville,Ind.,homeofDavidWilliams,52andofariverboatcasino(aplacewhereg
collision
随机试题
只属于纸质图书数字化加工环节的是()。
A.高血压病B.脑静脉畸形C.脑动脉瘤D.长骨骨折E.风湿性心脏病脑出血最常见的原因是
食后脘腹胀满,朝食暮吐,暮食朝吐,吐出宿谷不化,吐后即觉舒适,神疲乏力,面色少华,舌淡苔薄,脉细无力。应诊为
复式记账的基本理论依据是资产=负债+所有者权益。( )
以下事项中,决定资产评估价值的最主要因素是( )。
保险产品的功能主要有()。
我国的商业银行全部都是国有和由国家参股的银行。()
净现值法的优点有()。
《中华人民共和国教育法》第七十九条规定,在国家教育考试中作弊的,有权宣布考试无效的机构是()。
某LinuxDHCP服务器dhepd.conf的配置文件如下:ddns-update-stylenone;subnet192.168.0.0netmask255.255.255.0{range192.168.0.200192.168.0.254:i
最新回复
(
0
)