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
2024-08-18
16
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/3725208.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_eyyjsdz2005a_eyyjsdreadc_0863_20121[/img]Enyawasbornin19
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Therugbyshirtis
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Theordernumberf
[img]2012q2/ct_eyyjsdz2005b_eyyjsdreadc_0941_20121[/img][br]Youwearthejeans
[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]Thesoleoftheme
随机试题
建设工程设计单位对施工中出现的设计问题,应当采取下列()做法。A.应当及时解
《薪酬指引》规定,商业银行的基本薪酬一般不高于其薪酬总额的()。A.25%
关于行为评分的结果,一般认为评分越高,成为坏客户的可能性越高。( )
患者,男,70岁。咳嗽、咳痰,伴痰中带血3个月。胸片提示右肺门类圆形阴影,边缘毛
某男,30岁,长期嗜酒,中上腹疼痛8h,伴发热、恶心。既往体健。查体:患者弯腰抱
小量杏仁镇咳平喘作用是由于()。A.苦杏仁苷直接抑制咳嗽中枢B.分解出的氢氰酸
微循环的灌注状态取决于A:心功能、血容量、血压 B:心功能、周围血管张力、脉压
变电站站址标高要求:沿江、河、湖、海等受风浪影响的变电站,防洪设施标高还应考虑频
根据《企业会计准则》,若企业在资产负债表日提供劳务交易结果不能够可靠估计,且已经
【背景资料】某公司投资建设一蜡油深加工工程项目,经招标,由A施工单位总承包。该
最新回复
(
0
)