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
The climate of earth has fluctuated quite a bit over the last 4.6 billion years of our planet’s history and it can be expected t
The climate of earth has fluctuated quite a bit over the last 4.6 billion years of our planet’s history and it can be expected t
admin
2013-06-02
41
问题
The climate of earth has fluctuated quite a bit over the last 4.6 billion years of our planet’s history and it can be expected that the climate will continue to change. One of the most intriguing questions in earth science is whether the periods of ice ages are over or arc we living in an "interglacial" period of time between ice ages?
The geologic time period we are now living in is known as the Holocene (全新世). This epoch began about 11,000 years ago which was the end of the last glacial period and the end of the Pleistocene (更新世) epoch. The Pleistocene was an epoch of cool glacial and warmer interglacial periods which began about 1.8 million years ago.
Since the glacial period known as the "Wisconsin" in North America and "Wrm’ in Europe when over 10 million square miles (about 27 million km2 ) of North America, Asia, and Europe were covered by ice, almost all of the ice sheets covering the land and glaciers in the mountains have retreated. Today, about ten percent of the earth’s surface is covered by ice; 96% of this ice is located in Antarctica and Greenland. Glacial ice is also present in such diverse places as Alaska, Canada, New Zealand, Asia, and California.
As only 11,000 years has passed since the last Ice Age, scientists can not be certain that we are indeed living in a post- glacial Holocene epoch instead of an interglacial period of the Pleistocene and thus due for another ice age in the geologic future. Some scientists believe that an increase in global temperature, as we are now experiencing, could be a sign of an impending ice age and could actually increase the amount of ice on the earth’s surface.
The cold, dry air above the Arctic and Antarctica carries little moisture and drops little snow on the regions. An increase in global temperature could increase the mount of moisture in the air and increase the amount of snowfall. After years of more snowfall than melting, the Polar Regions could accumulate more ice.
An accumulation of ice would lead to a lowering of the level of the oceans and there would be further, unanticipated changes in the global climate system as well. Our short history on earth and our shorter record of the climate keeps us from fully understanding the implications of global warming. Without a doubt, an increase in the earth’s temperature will have major consequences for all life on this planet.
According to the passage Holocene ______.
选项
A、ended about 11,000 years ago
B、is an existing geologic time period
C、is the beginning of the Pleistocene epoch
D、is an epoch of cool glacial and warmer interglacial periods
答案
B
解析
细节题。由文章第二段第一句可知,B正确。
转载请注明原文地址:https://jikaoti.com/ti/uH5FFFFM
0
大学英语六级
相关试题推荐
IntheUnitedStates,itisrequiredthatallchildrenattendschool,publicorprivate,fortwelveyears.Thereare【B1】______t
IntheUnitedStates,itisrequiredthatallchildrenattendschool,publicorprivate,fortwelveyears.Thereare【B1】______t
IntheUnitedStates,itisrequiredthatallchildrenattendschool,publicorprivate,fortwelveyears.Thereare【B1】______t
______(这些水的痕迹使很多科学家相信)thattheremightbesomeformsoflifeonthatplanet.
TelevisionhastransformedpoliticsintheUnitedStatesbychangingthewayinwhichinformationisdisseminated,byalteringp
Everyonehasamomentinhistory,whichbelongsparticularlytohim.Itisthemomentwhenhisemotionsachievetheirmostpower
A、Dotheassignmentstowardstheendofthesemester.B、Quitthehistorycourseandchooseanotheroneinstead.C、Droponecours
ThehomeserviceindustryinBeijingisexpectedtobecomemoreattractivebothasajobandasanindustry.Sourcesatthe
随机试题
术后MODS中较容易和较早受到损害的器官是
在X线机电路中,高压整流器位于
下列各项与存货相关的支出中,不应计入存货成本的是()。
下列有关诉讼时效的表述中,错误的是()。
“五一黄金周”从存到废,现在又有不少人士认为应当恢复。就公共决策要求讲,早前“五一黄金周”之所以被废,并非是源于对假日经济好处的不了解,而恰恰是因为其人流的大量流动与环境影响,加上由人满为患所带来的不快乐等诸多原因存在而被取消。应该说.当时取消“五一黄金周
下列入物中,对西方作品的翻译或出版作出过较大贡献的有()等。
某房地产开发公司(以下简称A公司)在某市商业街开发了一幢商品楼,售价4000元/m2。某甲选中了其中一套三居室,双方签订了购房合同并于2004年2月1日办理了付款交房的手续,并且约定一年之内办理所有权证书。某甲因公需要出国一年,为了方便房屋的维护
你和同事小张共同完成一项工作,你的工作必须在小张完成后才能开展.但是小张是个慢性子。眼看完成工作的期限马上就要到了,如果小张还没有完成任务。那么就无法按期完成工作了。遇到这种情况你会怎么做?如果在工作开始前你就知道小张是个慢性子。你会怎么处理?
小明玩套圈游戏,套中小鸡一次得9分,套中小猴得5分,套中小狗得2分。小明共套了10次,每次都套中。每个小玩具都至少被套中一次。小明的总得分为61分,问他套中多少次小鸡?
一历史学学会有1260个会员,仅有525个会员参加理事长选举的投票。如果获胜的候选人的得票率是60%,问投票支持他的人占该会会员总数的百分之几?
最新回复
(
0
)