首页
登录
职称英语
The ocean bottom — a region nearly 2. 5 times greater than the total land ar
The ocean bottom — a region nearly 2. 5 times greater than the total land ar
游客
2023-12-27
4
管理
问题
The ocean bottom — a region nearly 2. 5 times greater than the total land area of the Earth — is a vast
frontier
that even today is largely unexplored and uncharted. Until about a century ago, the deep-ocean floor was completely
inaccessible
, hidden beneath waters averaging over 3, 600 meters deep. Totally without light and subjected to intense pressures hundreds of times greater than at the Earth’s surface, the deep-ocean bottom is a hostile environment to humans, in some ways as forbidding and remote as the void of
outer space
.
Although researchers have taken samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did not actually start until 1968, with the beginning of the National Science Foundation’s Deep Sea Drilling Project(DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP’s drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean’s surface and drill in very deep waters,
extracting
samples of sediments and rock from the ocean floor.
The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, the vessel logged 600,000 kilometers and took almost 20, 000 core samples of seabed sediments and rocks at 624 drilling sites around the world. The Glomar Challenger’s core samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to calculate what it will probably look like millions of years in the future. Today, largely on the
strength
of evidence gathered during the Glomar Challenger’s voyages, nearly all earth scientists agree on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth.
The cores of sediment drilled by the Glomar Challenger have also yielded information critical to understanding the world’s past climates. Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years, because they are largely isolated from the mechanical erosion and the intense chemical and biological activity that rapidly destroy much land-based evidence of past climates. This record has already provided insights into the patterns and causes of past climatic change — information that may be used to predict future climates. [br] The author refers to the ocean bottom as a "frontier" in Paragraph 1 because it______.
选项
A、is not a popular area for scientific research
B、contains a wide variety of life forms
C、attracts courageous explorers
D、is an unknown territory
答案
D
解析
推断题型。参看第一段第二行…vast frontier that even today is largely unexplored anduncharted.
转载请注明原文地址:https://www.tihaiku.com/zcyy/3309674.html
相关试题推荐
Thegreaterthepopulationthereisinalocality,thegreatertheneedforwate
AccordingtoUNICEF,around564millionIndians,nearlyhalfthepopulation,
AccordingtoUNICEF,around564millionIndians,nearlyhalfthepopulation,
AccordingtoUNICEF,around564millionIndians,nearlyhalfthepopulation,
AccordingtoUNICEF,around564millionIndians,nearlyhalfthepopulation,
AccordingtoUNICEF,around564millionIndians,nearlyhalfthepopulation,
Inthemajorpalmoilproducingregions,IndonesiaandMalaysia,itisestimated
Flints’findsintheregionextendingfromtheNileValleytothehighlandsofe
Insuranceisthesharingof【C1】________Nearlyeveryoneisexposed【C2】_______
Insuranceisthesharingof【C1】________Nearlyeveryoneisexposed【C2】_______
随机试题
Languagelearningbeginswithlistening.Individualchildrenvarygreatlyi
RitualChildKillingsSpreadAlarm,AngerinIvoryCoastAtleast21children
Wethankyouforyourorderthismonth,whichhasbeenputinwork.A、我们很感激您发出
【B1】[br]【B8】[audioFiles]audio_eusm_j01_273(20099)[/audioFiles]contribution所填词
第二类危险源中,环境因素是指机械设备、装置、元部件等由于性能低下而不能实现预定的
对外贸易往来是一国国际收支平衡的主要来源。下列关于对外贸易政策表述正确的是:A、
下列与固定资产折旧相关的说法中,正确的有()。A.企业至少应当于每年年度终了,
A.髂嵴上2横指 B.髂嵴下2横指 C.髂嵴水平 D.右髂前上棘至脐连线中
房地产经纪延伸服务是否收费由( )确定。A.价格管理部门 B.房地产经纪机构
《诗经》是中国最早的诗歌总集,按照乐调的不同分为风、雅、赋三类。()
最新回复
(
0
)