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
When Jules Verne wrote Journey to the Center of the Earth in 1864, there were many conflicting theories about the nature of the
When Jules Verne wrote Journey to the Center of the Earth in 1864, there were many conflicting theories about the nature of the
admin
2010-01-07
41
问题
When Jules Verne wrote Journey to the Center of the Earth in 1864, there were many conflicting theories about the nature of the Earth’ s interior. Some geologists thought that it contained a highly compressed ball of incandescent gas, while others suspected that it consisted of separate shells, each made of different materials. Today well over a century later, there is little direct evidence of what lies beneath our feet. Most of our knowledge of the Earth’ s interior comes not from mines or boreholes, but from the study of seismic waves--powerful pulses of energy released by earthquakes.
The way that seismic waves travel shows that the Earth’ s interior is far from uniform. The continents and the seabed are formed by the crust--a thin sphere of relatively light, solid rock. Beneath the crust lies the mantle, a different layer that extends approximately halfway to the Earth’ s center. There the rock is the subject of a battle between increasing heat and growing pressure.
In its high levels, the mantle is relatively cool; at greater depths, high temperatures make the rock behave more like a liquid than a solid. Deeper still, the pressure is even more intense, preventing the rock from melting in spite of a higher temperature.
Beyond a depth of around 2,900 kilometers, a great change takes place and the mantle gives way to the core. Some seismic waves cannot pass through the core and others are bent by it. From this and other evidence, geologists conclude that the outer core is probably liquid, with a solid center. It is almost certainly made of iron, mixed with smaller amounts of other elements such as nickel.
The conditions in the Earth’ s core make it a far more alien world than space. Its solid iron heart is subjected to unimaginable pressure and has a temperature of about 9,000°F. Although scientists can speculate about its nature, neither humans nor machines will ever be able to visit it.
Which of the following is a primary characteristic of the Earth’ s mantle?
选项
A、Light, solid rock.
B、Uniformity of composition.
C、Dramatically increasing pressure.
D、Compressed, incandescent gas.
答案
C
解析
本题为逻辑推理题,从第二段最后一句和第三段可以看出。
转载请注明原文地址:https://kaotiyun.com/show/AuPd777K
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
Throughoutourcountry,moreandmoreprivateschoolsaresetup.Somepeopledoubtabouttheeffectivenessoftheseprivatesch
Youreadanarticleinwhichtheauthorsays,"Iwouldliketoproposethatforsixtytoninetyminuteseacheveningrightafter
Whowouldbemostinterestedintheadvancesmentionedinthetalk?
SomepeopleusedtosaythatDadhadsomanychildrenthathecouldn’tkeeptrackofthem.Dadhimselfusedto【1】astoryabouto
SomepeopleusedtosaythatDadhadsomanychildrenthathecouldn’tkeeptrackofthem.Dadhimselfusedto【1】astoryabouto
Managersspendagreatdealoftheirtimeinmeetings.AccordingtoHenryMintzberg,inhisbook,TheNatureofManagerialWork,
Couldthebadolddaysofeconomicdeclinebeabouttoreturn?SinceOPECagreedtosupply-cutsinMarch,thepriceofcrudeoil
Evolutionarytheories.TheBelgianGeorgeLemaitreproposedtheideathatabout20,000millionyearsagoallthematterinthe
Couldthebadolddaysofeconomicdeclinebeabouttoreturn?SinceOPECagreedtosupply-cutsinMarch,thepriceofcrudeoil
随机试题
劳动监察的主体必须严格依据法律进行监察活动,被监察对象不得以任何方式规避监察执法活动,体现了劳动监察的()。
《茶馆》的文体是________,其作者是________。
Let’sworkhardtofind()totheproblem.
A.维生素DB.维生素AC.降钙素D.甲状旁腺激素E.生长激素抑制破骨细胞活性的物质是
追究当事人行政法律责任应当必须具备以下()条件。
国家助学贷款的还款方式包括()。
回购协议市场的交易特点有()。
股东大会年会应由董事会召集,并应在每一会计年度结束后()个月内召开。
国际货币体系的主要内容包括确定()。
给定程序MODll.C中函数fun的功能是:按以下递归公式求函数值。例如,当给n输入5时,函数值为18;当给n输入3时,函数值为14。请改正程序中的错误,使它能得出正确结果。注意:不要改动main函数,不得增行或删行,也不得更
最新回复
(
0
)