首页
登录
职称英语
[img]2012q2/ct_eyyjscz2008b_eyyjscreadb_0021_20121[/img] When was the last t
[img]2012q2/ct_eyyjscz2008b_eyyjscreadb_0021_20121[/img] When was the last t
游客
2023-10-19
32
管理
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. [br] It is a fact that frogs’ breeding cycle has been upset by worldwide increases in temperature.
选项
答案
N
解析
文章最后一句指明worldwide temperature increases are upsetting the breeding cycles of frogs是一个theory,而不是fact。
转载请注明原文地址:https://tihaiku.com/zcyy/3110638.html
相关试题推荐
[img]2012q2/ct_eyyjsdz2005a_eyyjsdreadc_0863_20121[/img]Enyawasbornin19
[img]2012q2/ct_eyyjsdz2005a_eyyjsdreadc_0863_20121[/img]Enyawasbornin19
[img]2012q2/ct_eyyjsdz2005a_eyyjsdreadc_0863_20121[/img]Enyawasbornin19
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Theordernumberf
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Theswimsuitcomes
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Youcangetthesw
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Itischeapertop
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Theleatherjacket
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Youcangettheme
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Thesoleoftheme
随机试题
Itwastwoyearsagotodaythatthehuntingbancameintoforce,supposedly
[originaltext]M:IhopeIdon’toversleep.Ihavegottocatchthefirstflight
[originaltext]Californiaisalandofvarietyandcontrast.Almosteveryty
TheInvisibleFuelProvidesEnsuranceforEnergySecurityintheFut
WhyYouShouldn’tFreakOutAboutSwarmingHoneybees—andHowtoSaveBeesFr
基金管理人、基金托管人和其他基金信息披露义务人应当依法披露基金信息,并保证所披露
杆体细胞能分辨物体的()。单选A.细节和颜色 B.明暗和颜色 C.轮廓
2020年10月境外广告公司为境内甲企业提供广告服务,合同含税价款100万美元,
B公司生产、销售一种产品,该产品的单位变动成本为60元,单价为80元。公司目前采
D公司是从事普通民用机械制造的中央企业,正在编制下一年度预算。根据其前8个月的经
最新回复
(
0
)