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
Most of-us are used to seasons. Each year, spring follows winter, which follows au-tumn, which follows summer, which follows spr
Most of-us are used to seasons. Each year, spring follows winter, which follows au-tumn, which follows summer, which follows spr
admin
2011-01-14
31
问题
Most of-us are used to seasons. Each year, spring follows winter, which follows au-tumn, which follows summer, which follows spring. And winter is colder than summer.But the earth goes through temperature cycles over much longer periods than those that we experience. Between 65,000 and 35,000 years ago, the planet was much colder than it is now. During that time the temperature also changed a lot, with periods of warming and cooling. Ice melted during the warm periods, which made sea levels rise. Water froze again during the cold periods.
A new study from Switzerland sheds light on where ice sheets melted during the ice age.
It now seems that the ice melted at both ends of the earth, rather than just in ei-ther northern or southern regions.
This surprised the researchers from the University of Bern.
Scientists have long assumed that most of the ice that melted was in the Northern hemisphere (半球) during the 30,000-year long ice age.
That belief was held because the North Pole is surrounded by land, while the South Pole is surrounded by the Antarctic Ocean. It is easier for ice sheets to grow on land. If surrounded by sea the ice can easily just slip into the ocean instead of building up.
The researchers used a computer model to look at ways the ice could melt and how it might affect sea levels. They compared these results to evidence of how temperatures and currents actually changed during that time. The model showed that if it was only in the Northern hemisphere that ice melted, there would have been a bigger impact (影响) on ocean currents (洋流) and sea temperatures than what actually happened. Studies suggest that melting just in the Southern hemisphere would have been impossible, too. The only reasonable conclusion, the scientists could make, was that ice melted equally in the North and the South.
It is still a mystery as to what caused the temperature changes that caused the ice to melt.
The scientists are not sure______.
选项
A、how long the ice age lasted
B、where ice sheets melted during the ice age
C、what caused the temperature changes
D、what the earth is made up of
答案
C
解析
事实细节题。根据文章最后一句It is still a mystery as to what caused the temperature changes that caused the ice to melt.可知科学家们现在还没有找到引起温度变化的原因。
转载请注明原文地址:https://kaotiyun.com/show/T8JO777K
0
成人本科学位英语
相关试题推荐
CalvinCoolidge(1872—1933)wasthethirtiethpresidentoftheUnitedStates.Helookeddownonapersonasbeingunworthyofre
CalvinCoolidge(1872—1933)wasthethirtiethpresidentoftheUnitedStates.Helookeddownonapersonasbeingunworthyofre
Wefindthatbrightchildrenarerarelyheldbackbymixed-abilityteaching.Onthecontrary,boththeirknowledgeandexperienc
What,besideschildren,connectsmothersaroundtheworldandacrosstheseasoftime?It’schickensoup,oneprominentAmerican
Atsometimeinyourlifeyoumayhaveastrongdesiretodosomethingstrangeorterrible.However,chancesarethatyoudon’t
OnJune17,1744,theofficialsfromMarylandandVirginiaheldatalkwiththeIndiansoftheSixNations.TheIndianswereinv
Moresurprising,perhaps,thanthecurrentdifficultiesoftraditionalmarriageisthefactthatmarriageitselfisaliveandth
RelationsbetweentheUnitedStatesandColombiasufferedformanyyearsbecauseofanincidentinvolvingtheRepublicofPanama
Thedifferencesinlivingstandardsaroundtheworldarevast.In1993,theaverageAmericanhadanincomeofabout$25,000.Inthe
Duringrecentyearswehaveheardmuchabout"race":howthisracedoescertainthingsandthatracebelievescertainthingsand
随机试题
四肢厥冷可见于
某妇,30岁,闭经1年,体重明显增加,脸上痤疮越来越多,内分泌性雄性激素高出正常2倍,B超检查示双侧卵巢体积分别为5cm×4.3cm×2.7cm,4.8cm×4.5cm×3.0cm,该患者属于哪种闭经()
患者,女性,24岁,顺产,胎盘娩出后半小时内阴道出血500ml,色红。查看胎盘完整,见有血管中断于胎膜边缘。其出血原因最可能是
A.干热灭菌法B.热压灭菌法C.流通蒸汽灭菌法D.煮沸灭菌法E.辐射灭菌法用高温干热空气灭菌的方法
发展规划体现政策性,一定要()。
旅行社给客户寄送产品宣传价目表属于()的行为。
关于法的分类的说法正确的是()。
甲、乙通过丙向丁购买毒品,甲购买的目的是为自己吸食,乙购买的目的是为贩卖,丙则通过介绍毒品买卖,从丁处获得一定的好处费。对于本案,下列选项正确的是()。
我们伟大的民族精神的主要内容包括
From:production@cpccom.comTo:packingdepa@ntn.com.enSubject:PackingrequirementsDearSirs,OnFebruary20th,werecei
最新回复
(
0
)