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 was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet area
When was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet area
admin
2011-01-05
29
问题
When was the last time you saw a frog? Chances are, if you live in a city, you have not seen one for some time. Even in wet areas once teeming with frogs and toads, it is becoming less and less easy to find those slimy, hopping and sometimes poisonous members of the animal kingdom. All over the world, even in remote jungles on the far side of the globe, frogs are losing the ecological battle for survival, and biologists are at a loss to explain their demise. Are amphibians
simply over-sensitive to changes in the ecosystem? Could their rapid decline in numbers be signalling some coming environmental disaster for us all?
This frightening scenario is in part the consequence of a dramatic increase over the last quarter of a century in the development of once natural areas of wet marshland; home not only to frogs but to all manner of wildlife. Yet, there are no obvious reasons why certain frog species are disappearing from rainforests in the Southern Hemisphere which are barely touched by human hands. The mystery is unsettling to say the least, for it is known that amphibian species are extremely sensitive to environmental variations in temperature and moisture levels. The danger is that planet Earth might not only lose a vital link in the ecological food chain (frogs keep populations of otherwise pestilent insects at manageable levels) , but we might be increasing our output of air pollutants to levels that may have already become irreversible. Frogs could be inadvertently warning us of a catastrophe.
An example of a bizarre occurrence regarding a species of frog dates from the summer of 1995 , when "an explosion” of multi-coloured frogs of the species Rana klepton esculenta occurred in the Netherlands. Normally these frogs are brown and greenish-brown, but some unknown contributory factor is turning these frogs yellow and / or orange. Nonetheless, so far, the unusual bi- and even tri-coloured frogs are functioning similarly to their normal-skinned contemporaries. It is thought that frogs with lighter coloured skins might be more likely to survive in an increasingly warm climate due to global warming.
One theory put forward to explain extinct amphibian species that seems to fit the facts concerns the depletion of the ozone layer, a well-documented phenomenon which has led to a sharp increase in ultraviolet radiation levels. The ozone layer is meant to shield the Earth from UV rays, but increased radiation may be having a greater effect upon frog populations than previously believed. Another theory is that worldwide temperature increases are upsetting the breeding cycles of frogs.
Biologists are unable to explain why frogs are dying out.
选项
答案
Y
解析
第一段提到的“biologists are at a loss to explain their demise”与本题陈述相符。at a loss是“困惑,无计可施”的意思,与“unable”同义。demise是“死亡”的意思,与“dieout”同义。
转载请注明原文地址:https://kaotiyun.com/show/KJVK777K
本试题收录于:
C类竞赛(非英语专业本科)题库大学生英语竞赛(NECCS)分类
0
C类竞赛(非英语专业本科)
大学生英语竞赛(NECCS)
相关试题推荐
(1)SANFRANCISCO—Aftermonthsoffeverishspeculation,StevenP.JobsintroducedWednesdaywhatApplehopeswillbethecoole
(1)You’rebusyfillingouttheapplicationformforapositionyoureallyneed;let’sassumeyouonceactuallycompletedacoup
(1)WhenIwasvisitingShanghai,Ilearnedtoavoidacertainalleyonmywalktotheundergroundsystem.Italwayssmelledinc
Therehavebeenanumberofstudiesonsmokingamongtheyoung.【T1】________,ithasbeenfoundthatmanyofthechildrenliving
NewwordsentertheEnglishlanguageallthetime.Infact,Englishhasalwaysbeeninastateof【T1】________.Andinrecentyea
A、Becausehelackedworkexperience.B、Becausehehadatightclassschedule.C、Becausethelocationsofthosefirmswereremote
Britain’spressisunusual________itisdividedintotwoverydifferenttypesofnewspaper:thequalitypressandthepopularpr
A、Theycangetperfectbodyshape.B、Theycanmakefriendshavingthesamehobby.C、Theycanenjoythenaturalenvironment.D、Th
Thepublicopinionwasthatthetimewasnot________fortheelectionofsucharadicalcandidateasMr.Jones.
Then________wehadbeenlookingforwardto.
随机试题
在低于30℃的环境中,人体24小时的不感蒸发量一般为
按演练方式不同,应急演练可以分为()
按资产评估的具体对象划分,资产评估报告可分为()。
甲公司向乙银行借款100万元,双方签订质押合同,约定以甲公司持有的丙上市公司的股权设定质押。根据物权法律制度的规定,下列说法正确的有()。
下列有关注册会计师审计和政府审计的共同点的说法中,正确的是()。
Youaregoingtoreadatextaboutbeingabetterfriend,followedbyalistofimportantways.Choosethebestwayfromthelis
某旅行社导游小孟正在制作一份介绍首都北京的演示文稿,按照下列要求帮助她组织材料完成演示文稿的整合制作,完成后的演示文稿共包含19张幻灯片,其中不能出现空白幻灯片。为第18张幻灯片应用“标题和表格”版式,取消其中文本上的超链接,并将其转换为一个表格,改变
______suchagoodchance,heplannedtolearnmore.
Ofcourse,thenotionsuspectsthatwhilepeoplework50weeksayear,theiroutputisgreaterthantheywork46or47weeks.
A、20minutes.B、13minutes.C、15minutes.D、30minutes.C数字题。对话中女士说她的表慢了20分钟,男士说他总是把他的表拨快15分钟,女士觉得这是个好办法,于是决定将她的表拨快30分钟。因此答案为C。
最新回复
(
0
)