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
Older Volcanic Eruptions Volcanoes were more destructive in ancient history, not because they were bigger,but because the ca
Older Volcanic Eruptions Volcanoes were more destructive in ancient history, not because they were bigger,but because the ca
admin
2016-08-16
31
问题
Older Volcanic Eruptions
Volcanoes were more destructive in ancient history, not because they were bigger,but because the carbon dioxide(二氧化碳)they released wiped out life with greater ease.
Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruption skilled off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava(熔岩)that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals.
The Permian(二叠纪)extinction, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes(十亿吨)of carbon as carbon dioxide. The global warming that followed wiped out 80 percent of all marine genera(种类)at the time, and it took 5 million years for the planet to recover. Yet 60 million years ago, there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within tens of thousands of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs(恐龙)65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid(小行星). He thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO
2
.
Vincent Courtillot, director of the Paris Geophysical Institute in France, says that Wignall’ s idea is provocative. But he says it is incredibly hard to do these sorts of calculations. He points out that the killing power of volcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years. He also adds that it is difficult to estimate how much lava prehistoric volcanoes produced, and that lava volume may not necessarily correspond to carbon dioxide emissions.
Older volcanic eruptions did more damage than more recent ones because______.
选项
A、older volcanoes were brighter
B、carbon dioxide made the earth much warmer
C、older volcanoes were hotter
D、carbon dioxide killed off life more easily
答案
D
解析
根据首段末尾but because the carbon dioxide(二氧化碳)they released wiped out lifewith greater ease可知古老的火山喷发的二氧化碳更轻易地灭绝地球上的生物。故选D。
转载请注明原文地址:https://kaotiyun.com/show/ohGd777K
本试题收录于:
职称英语理工类A级题库职称英语分类
0
职称英语理工类A级
职称英语
相关试题推荐
GeologyandHealthTheimportanceofparticularmetalsinthehumandiethasbeenrealisedwithinthepastfewdecades,and
DevelopmentinNewspaperOrganizationOneofthemostimportantdevelopmentsinnewspaperorganizationduringthefirstpart
HumanIngenuitySincethedawnofhumaningenuity,peoplehavedevisedevermorecunningtoolstocopewithworkthatisda
EnglishandEnglishCommunityThereisnodenyingthatEnglishisausefullanguage.ThepeoplewhospeakEnglishtodaymake
EnglishandEnglishCommunityThereisnodenyingthatEnglishisausefullanguage.ThepeoplewhospeakEnglishtodaymake
AccordingtoRobertBell,ifmobilephonesprovetobedangeroustopeople’shealth,Whoabsorblow-levelradiationatahigher
RecyclingAroundtheWorldRecyclingisoneofthebestenvironmentalsuccessstoriesofthelate20thcentury.Butwecoulddo
WeavingwithLightIntheSierraMadremountainrangeofwestcentralMexico,thenativeHuicholpeoplelivemuchthewayth
Thecityhasdecidedtodoawaywithalltheoldbuildingsinitscenter.
随机试题
2013年4月,陈明设立A有限责任公司(简称“A公司”),从事绿色食品开发,注册资本为200,万元。A公司成立半年后,为增加产品开发力度,陈明拟新增资本100万元,并为此分别与张巡、李贝洽谈,该二人均有意愿认缴全部新增资本,加入陈明的公司。陈明遂先后与张巡
间接碘量法的标准滴定溶液是硫代硫酸钠溶液。
简述灰色市场活动的弊端。
()性包含顽强斗争的品质。
甲有父亲、母亲、配偶(机关干部)、儿子(工程师)、女儿(小学音乐教师)各一人。甲去世,留有遗产,房屋6间、荷款5000元、古字画10件和钢琴一架。甲生前自书遗嘱指定:房产归妻子和儿女继承,古字画赠给文物部门。对存款和钢琴遗嘱未作处理。现甲的女儿提出要将钢琴
关于特发性血小板减少性紫癜(ITP)的概念,描述错误的是()
业主是()。
人类的四大烦恼,不但“生”“老”“死”没人躲过,就是“病”也无法根除,人类自有“药”的发明,“药”与“病”就“道高一尺,魔高一丈”。虽然在“药”不太灵的时候,行气、导引、祝由(古代的精神疗法)会重新产生吸引力(如对外丹术衰落后的内丹术和出于绝望的癌症病人)
简述泰勒原理。
社会经济权是指公民享有的经济生活和物质利益方面的权利,是公民实现其他权利的物质基础。主要包括
最新回复
(
0
)