首页
登录
职称英语
What accounts for the low-lying, flat surface of Mars’s north? On Earth’s su
What accounts for the low-lying, flat surface of Mars’s north? On Earth’s su
游客
2024-01-10
17
管理
问题
What accounts for the low-lying, flat surface of Mars’s north? On Earth’s surface, higher- and lower-lying areas have different types of crust: one, thin and dense, is pulled toward Earth’s center more strongly by gravity, and the planet’s water naturally comes to sit over it, creating oceans. The processes that generate this oceanic crust drive plate tectonics.
Is Mars’s north similarly characterized by a sort of crust different from other areas of the planet? Some researchers do see signs of tectonic activity surrounding the northern basin that suggest that it was created through the formation of new crust, like ocean basins on Earth. However, McGill points to northern bedrock structures that predate the features said to mark the start of the tectonic process. McGill instead believes that through some novel mechanism the ancient surface sank to its current depth as a single unit. This would explain why features around the basin’s edge, which would have formed as the surface dropped, seem to be younger than structures at its floor.
The third possibility is that the northern lowlands result from impacts. Some researchers suggest they formed as a series of big overlapping impact craters. Others arguing that the odds against such a pattern of impacts are large, postulate a single event—the impact of an object bigger than any asteroid the solar system now contains. [br] The primary purpose of the passage is to
选项
A、explore an analogy between aspects of the geology of Mars and the geology of Earth.
B、describe how a certain feature of Mars’s surface formed.
C、point out the effect that new data has had on a scientific investigation.
D、summarize potential explanations of a large-scale geological feature.
E、present the rationale for a scientist’s theory and expose some of its weaknesses.
答案
D
解析
a large scale geological feature对应火星北部盆地,potential explanations对应文中三种观点。根据第三段第一句The third possibility可知,文中三种观点均为可能性的推测,没有定论,因此对应该项的potential。
转载请注明原文地址:https://tihaiku.com/zcyy/3349663.html
相关试题推荐
Whatisthesurfaceareaofarightrectangularsolidwithdimensions4by7by
Whatisthesurfaceareainsquareinchesofacubewhosevolumeis216cubicin
Fortherectangularsolidbelow,findthefollowing.(a)Surfaceareaofthesoli
Fortherectangularsolidbelow,findthefollowing.(a)Surfaceareaofthesoli
Howmuchlongeristheedgeofacubewithasurfaceareaof1,350thantheedge
Scientistsbelievethatbyraisingatmosphericpressureandsurfacetemperature,
Scientistsbelievethatbyraisingatmosphericpressureandsurfacetemperature,
Whenhomeisapproximately2,000feetunderthesurfaceofthesea,itischalle
Thegapsinexistingaccountsoftheplaywrightslifearenot(i)______,sincemu
Beforeabout1960,virtuallyallaccountsofevolutionassumedmostadaptationt
随机试题
PoorpeoplehaveIQ’ssignificantlylowerthanthoseofrichpeople.The【S1】
Expertsinthefoodindustryarethinkingalotabouttrashthesedays.Rest
变压器冲击耐压试验是用以检验变压器的()属性。A.主绝缘 B.纵绝缘 C.
某地一位司机在车祸中受重伤,被同行的人送到附近一家医院抢救。经查:伤员多发性骨折
颅骨线形骨折下列哪项不正确()A.单纯线形骨折本身不需特殊处理 B.骨折
孕妇陈某,28岁,G1P0,孕39周,未经产前检查,诉下肢水肿半月,近3日头痛,
饥不欲食的病机是( )。A.脾失健运 B.肝强脾弱 C.胃阴不足 D.胃
易并发浆细胞白血病的多发性骨髓瘤的M蛋白的类型是A.IgG型B.IgA型C.Ig
关于住房出租和转让的税收制度,说法正确的()。A:个人转让自用五年以上,并且是家
在人类社会经济制度演变的各个阶段都起作用的经济规律是()。A.价值规律
最新回复
(
0
)