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
Surface Fluids on Venus and Earth P1: When astronomers first pointed their rudimentary telescopes at Venus, they saw a world shr
Surface Fluids on Venus and Earth P1: When astronomers first pointed their rudimentary telescopes at Venus, they saw a world shr
admin
2018-10-18
80
问题
Surface Fluids on Venus and Earth
P1: When astronomers first pointed their rudimentary telescopes at Venus, they saw a world shrouded in clouds. Here on Earth, clouds mean water, so early astronomers imagined a tropical world with constant rainfall. The truth, of course, is that the hydrological state on Venus is quite different from that of Earth. The hydrologic cycle describes the continuous movement of liquid above, on, and below the surface of a planet. These movements derive their energy from the Sun and the gravitational forces of the planet itself, and in turn redistribute energy around the globe through atmospheric circulation. As fluids interact with surface materials, water molecules move particles repeatedly through solid, liquid, and gaseous phases or react chemically with them to modify and produce materials. On a solid planet with a hydrosphere and an atmosphere, only a tiny fraction of the planetary mass flows as surface fluids. Yet, the movements of these fluids can drastically alter a planet.
P2: Imagine Venus a long time ago. The planet is nearly identical to the Earth in size, mass, composition and distance from the Sun. However, it lacks any sign of a hydrologic system—there are no streams, lakes, oceans, or glaciers. It begins like the Earth with global oceans, carbon dioxide dissolved in the oceans, and carbonate rocks forming at the bottoms of the oceans. But because Venus is just a tiny bit smaller than the Earth, it has less radioactive heat sources inside. Thus, at some time in the distant past, perhaps only 500 million to 1 billion years ago, Venus may have run out of enough internal heat to continue to drive the tectonic activity. Alternatively, because Venus is a little closer to the Sun, we would expect that the original temperature of Venus should have been a little warmer than that of the early Earth. The slightly elevated temperature puts a bit more water in the oceans and atmosphere and a bit less in the rocks. This makes the rocks harder since water serves as a lubricant for the plate tectonic process. Either way, tectonic activity begins to slow down. Because Venus receives more heat from the Sun, water released from the interior evaporated and rose to the upper atmosphere, where the Sun’s ultraviolet rays broke the molecules apart. Much of the freed hydrogen escaped into space, and Venus lost its water. Without water, Venus became less and less like Earth and kept an atmosphere filled with carbon dioxide. On Earth, liquid water removes carbon dioxide from the atmosphere and combines it with calcium, through rock weathering, to form carbonate sedimentary rocks. Without liquid water to remove carbon from the atmosphere, prohibiting the formation of carbonate minerals, the level of carbon dioxide in the atmosphere of Venus remains high.
P3: Like Venus, Earth is large enough to be geologically active and for its gravitational field to hold an atmosphere. But fortunately, being further away, it has less heating from the sun and allows water to exist as a liquid, a solid, and a gas. Water is thus extremely mobile and moves rapidly over the planet in a continuous hydrologic cycle. Driven by energy from the sun, water is constantly being cycled from the ocean, through the atmosphere, and ultimately back to the oceans. As a result, Earth’s surface has been continually changed and eroded into delicate systems of river valleys—a remarkable contrast to the surfaces of other planetary bodies where impact craters dominate. Other geologic changes occur when the gases in the atmosphere or water react with rocks at the surface to form new chemical components with different properties. Weathering breaks down rocks into gravel, sand, and sediment, and is an important source of key nutrients such as calcium and sulfur. Estimates indicate that, on average, Earth’s surface weathers at a rate of about 0.5 millimeter per year. Actual rates may be much higher at specific locations and may have been accelerated by human activities. However, none of these would have happened if our planet had spun a little further from or nearer to the sun. Because liquid water was present, self-replicating molecules of carbon, hydrogen, and oxygen developed life early in Earth’s history and have rapidly modified its surface, blanketing huge parts of the continents with greenery.
P2: Imagine Venus a long time ago. The planet is nearly identical to the Earth in size, mass, composition and distance from the Sun. ■ However, it lacks any sign of a hydrologic system—there are no streams, lakes, oceans, or glaciers.■ It begins like the Earth with global oceans, carbon dioxide dissolved in the oceans, and carbonate rocks forming at the bottoms of the oceans. ■But because Venus is just a tiny bit smaller than the Earth, it has less radioactive heat sources inside. Thus, at some time in the distant past, perhaps only 500 million to 1 billion years ago, Venus may have run out of enough internal heat to continue to drive the tectonic activity. Alternatively, because Venus is a little closer to the Sun, we would expect that the original temperature of Venus should have been a little warmer than that of the early Earth. The slightly elevated temperature puts a bit more water in the oceans and atmosphere and a bit less in the rocks. This makes the rocks harder since water serves as a lubricant for the plate tectonic process. Either way, tectonic activity begins to slow down. Because Venus receives more heat from the Sun, water released from the interior evaporated and rose to the upper atmosphere, where the Sun’s ultraviolet rays broke the molecules apart. ■ Much of the freed hydrogen escaped into space, and Venus lost its water. Without water, Venus became less and less like Earth and kept an atmosphere filled with carbon dioxide. On Earth, liquid water removes carbon dioxide from the atmosphere and combines it with calcium, through rock weathering, to form carbonate sedimentary rocks. Without liquid water to remove carbon from the atmosphere, prohibiting the formation of carbonate minerals, the level of carbon dioxide in the atmosphere of Venus remains high.
Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
选项
A、Life on Earth is responsible for many changes to the planet’s surface, including blankets of greenery.
B、Self-replicating molecules of carbon, hydrogen, and oxygen led to the development of life early in Earth’s history.
C、The presence of water made it possible for life to develop early in Earth’s history and to significantly change its surface.
D、Early in life’s history on Earth, self-replicating molecules of carbon, hydrogen, and oxygen began blanketing the surface in greenery.
答案
C
解析
【句子简化题】文中句子提到了一对因果关系,并且结果包括两个——产生生命和改变地表形态,满足文中逻辑同时包括了所有信息的是答案C。
转载请注明原文地址:https://kaotiyun.com/show/1wfO777K
0
托福(TOEFL)
相关试题推荐
ChooseTWOletters,A-E.WhichTWOsubjectsdidMartinalikebestbeforegoingtouniversity?AArtBHistoryCFrenchDEnglish
ChooseTWOletters,A-E.WhichTWOsubjectsdidMartinalikebestbeforegoingtouniversity?AArtBHistoryCFrenchDEnglish
BeforeyoulistenLookatthetaskbelow.Trytoworkoutthesituationfromthetask.Whataretheytalkingabout?Whyarethey
A、Bygreatlyincreasingtheocean’sdepthinsomeareas.B、Bycreatinglargewavesonthesurfaceoftheocean.C、Bycausingmud
(Heat)exhaustionis(causing)byexcessive(loss)ofbody(fluids)andbodysalts.
Thewaterof(the)Atlantic,Pacific,andIndianOceans(makeup)70.8percent(to)theEarth’s(surface).
A、TheMoonhasnowaterB、TheMoon’smaterialscamefromEarth’scoreC、TheMoon’scorediffersfromitssurfaceD、TheMooncont
Sinceprehistorictimes,artists(havebeen)arrangedcolorsonsurfaces(inways)(thatexpress)theirideas(aboutpeople),the
______..includingclimate,mineralcontent,andthepermanencyofsurfacewater,wetlandsmaybemossy,grassy,scrubby,orwoo
Bothhumansandcetaceanshavelargebrainswithanexpandedanddistinctivelyfoldedsurface,thecortex.Thecortexisthedom
随机试题
A.12.5molATPB.15molATPC.10molATPD.32molATP1mol丙酮酸彻底氧化产生
A.内窥镜检查B.脱落细胞检查C.超声波断层检查D.甲胎蛋白定量测定E.选择性动脉造影是一种非侵入性检查方法()
在下列行为中,不符合暂停施工规定的是()。
某公路隧道为浅埋隧道,设计净高5.0m,净宽14.0m,隧道长280m。隧道区域内主要为中等风化岩石,隧道区域内地表水系较发育,区域内以基岩裂隙水为主,浅部残坡积层赋存松散岩类孔隙水,洞口围岩变化段水系较发达。施工单位针对隧道的特点,加强了浅埋段和洞口段的
甲公司为上市公司,采用授予职工限制性股票的形式实施股权激励计划。2×17年1月1日,公司以非公开发行方式向100名管理人员每人授予10万股自身股票(每股面值为1元),授予价格为每股6元。当日,100名管理人员全部出资认购,总认购款项为6000万元,甲公司履
投保决策的过程正确的是()。
承认“人类的一切认识都具有相对性”是()。
DiscussionoftheassimilationofPuertoRicansintheUnitedStateshasfocusedontwofactors:socialstandingandthelossof
牛顿力学统领科学200多年,它的结果被广泛验证和成功应用,在科学史上,是最具权威性的理论。但是,20世纪初,爱因斯坦的理论揭示了牛顿力学的实质性局限,超越了这个长期以来被认为是最成功的科学理论。如果上述断定为真,以下哪项一定为真?()
A—airtrafficcontrolsystemJ—safetyprecautionmeasureB—armedpoliceK—safetycontroldeviceC—crimepreventionL—securityco
最新回复
(
0
)