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
41
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.
Attempts are being made to halt the development of wet marshland.
选项
答案
NG
解析
转载请注明原文地址:https://kaotiyun.com/show/OJVK777K
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)AmassiveearthquakestruckHaitijustbefore5p.m.onJan.12,about10milessouthwestofPort-au-Prince,thecountry’sc
(1)You’rebusyfillingouttheapplicationformforapositionyoureallyneed;let’sassumeyouonceactuallycompletedacoup
PASSAGEONEWhichtwocountriesinvestedthemostinAustralia?(Pleaseanswerinadescendingorder.)
Therehavebeenanumberofstudiesonsmokingamongtheyoung.【T1】________,ithasbeenfoundthatmanyofthechildrenliving
NewwordsentertheEnglishlanguageallthetime.Infact,Englishhasalwaysbeeninastateof【T1】________.Andinrecentyea
ReadingFasterTheonlywaytoreadfasteristoreadfaster,anditisaserioussuggestion.【T1】________onspeedreadi
A、Enjoyingalcoholicdrinks.B、Goingtochurch.C、Openingpresents.D、Holdingpublicevents.D原文中,女士询问男士圣诞节是否有放烟花或其他的公共活动,男士回答说没
A、It’shardtogetaseat.B、It’stoodangerous.C、It’stoocrowded.D、It’stoohot.B由原文可知,男士的妻子坐公交车上班,但有时候很难找到座位,而且车上又挤又热,故排除A
(1)Itisrareforataleofacademicmismanagementinasmallinstitutiontograbnationalattention.ButSciences-Poisnoord
ThousandsofyoungAustraliansareheadingbackthecouchwithabagofpopcorn,withonechildineveryfourclassifiedasover
随机试题
不出现心绞痛症状的疾病是
《孙子兵法》中包含的战略管理思想包括_______、_______、______。
伴有砂粒体的甲状腺癌是
男性,68岁,饱餐后突感上腹部激烈疼痛,伴呕吐、大汗及濒死感2小时入院。急诊查心率110次/分,血压85/60mmHg,心电图示V1~V5导联ST段呈弓背向上抬高,律不齐。若发生了心室颤动,护十采取的处理措施正确的是
吴茱萸善治何种头痛
交易型开放式指数基金和上市开放式基金均属于特殊类型基金。()
采用排队法进行考评时,为了提高考评质量,应采用()。
下列我国的世界遗产所在省(区)不属于黄河流域的是:
在概念转变的影响因素中,学习者先前知识经验的()特征影响转变的可能性。
设b>a>0,证明:.
最新回复
(
0
)