首页
登录
职称英语
It is now well-established that petroleum migrates through aquifers and can
It is now well-established that petroleum migrates through aquifers and can
游客
2024-01-02
67
管理
问题
It is now well-established that petroleum migrates through aquifers and can become trapped in reservoirs. Petroleum migration is analogous to groundwater migration. When oil and gas are squeezed out of the shale in which they originated and enter a body of sandstone or limestone somewhere above, they migrate readily because sandstone (consisting of quartz grains) and limestone (consisting of carbonate minerals) are much more permeable than any shale.
The force of molecular attraction between oil and quartz or carbonate minerals is weaker than that between water and quartz or carbonate minerals.
Hence, because oil and water do not mix, water remains fastened to the quartz or carbonate grains, while oil occupies the central parts of the larger openings in the porous sandstone or limestone. Because oil is lighter than water, it tends to glide upward past the carbonate- and quartz-held water. In this way, oil becomes segregated from the water; when it encounters a trap, it can form a pool.
Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail. The tolerance range in body temperature represents the range of temperatures within which a species can survive. One species of North American newt is still active when temperatures drop to -2℃, while one
South American frog
feels comfortable even when temperatures rise to 41℃—the highest body temperature measured in a free-ranging amphibian. Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of -6℃ with approximately one third of their body fluids frozen. The other tissues are protected because they contain the frost-protective agents glycerin or glucose. Additionally, in many species, the tolerance boundaries are flexible and can change as a result of acclimatization (long-term exposure to particular conditions).
While many other observers and thinkers had laid the groundwork for science, Thales (circa 624 B.C.— circa 547 B.C.), the best known of the earliest Greek philosophers, made the first steps toward a new, more objective approach to finding out about the world. He posed a very basic question:
"What is the world made of?"
Many others had asked the same question before him, but Thales based his answer strictly on what he had observed and what he could reason out—not on imaginative stories about the gods or the supernatural. He proposed water as the single substance from which everything in the world was made and developed a model of the universe with Earth as a flat disk floating in water. [br] Why does the author mention a "South American frog" species in the passage?
选项
A、To make the point that an amphibian’s temperature tolerance depends on a number of factors
B、To indicate how precise the range of body temperatures is for certain amphibians
C、To contrast its ability to adapt to that of the North American newt
D、To help illustrate the range of environmental conditions to which amphibians have adapted
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3327666.html
相关试题推荐
TheArcticfoxisfoundthroughouttheArctic,usuallyontundraormountains__
Oxygenandnutrientsreachthebody’stissues______fromthebloodthroughthe
______arechieflyderivedfrompetroleum.A、PlasticstodayB、Thereareplastics
(Through)hisessays,poems,andlectures,RalphWaldoEmersonestablished(hims
TheScienceofAnthropologyAThroughvariousmethodsof
TheScienceofAnthropologyAThroughvariousmethodsof
TheScienceofAnthropologyAThroughvariousmethodsof
TheScienceofAnthropologyAThroughvariousmethodsof
TheScienceofAnthropologyAThroughvariousmethodsof
Moreover,gettingpetroleumoutofthegroundandfromundertheseaandto
随机试题
Themanagementandstaffarehappytowelcomeyouandwilldoalltheycant
整理形态代表当前市场暂时休整,下一步市场运动将与此前趋势的原方向反转。()A、正确B、错误B整理形态代表当前市场暂时休整,下一步市场运动将与此
[originaltext]Hello,viewers.TodayI’mstandingata2,000-year-oldRoman-era
A.允许在左侧车道行驶 B.分隔对向行驶的交通流 C.分隔同向行驶的交通流
根据我国民法总则的规定,以下属于限制民事行为能力人的是______。A、9周岁的
A
香附、乌药、木香具有的共同功效是()A.降逆止呃 B.疏肝解郁 C.行
Jb2232018.变电站智能巡检机器人能完成哪些工作?(5分)
某企业拟开发一项新技术,经测算,开发该项新技术的总投资为500万元,新技术的寿命
【2013案例四~4】 【背景资料】 某安装公司承建一高层商务楼的机电工程
最新回复
(
0
)