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
Where Have All the Frogs Gone? In the 1980s, scientists around the world began to notice something strange: Frogs were disapp
Where Have All the Frogs Gone? In the 1980s, scientists around the world began to notice something strange: Frogs were disapp
admin
2009-06-15
61
问题
Where Have All the Frogs Gone?
In the 1980s, scientists around the world began to notice something strange: Frogs were disappearing. More recent research has shown that many kinds of amphibians (两栖动物) are declining or have become extinct. They have been around for a long time - over 350 million years. Why are they dying out now?
Scientists are seriously concerned about this question. First of all, amphibians are an important source of scientific and medical knowledge. By studying amphibians, scientists have learned about new substances that could be very useful for treating human diseases. Further research could lead to many more discoveries, but that will be impossible if the amphibians disappear.
The most serious aspect of amphibian loss, however, goes beyond the amphibians themselves. Scientists are beginning to think about what amphibian decline means for the planet as a whole. If the earth is becoming unlivable for amphibians, is it also becoming unlivable for other kinds of animals and human, beings as well?
Scientists now believe that amphibian decline is due to several environmental factors. One of these factors is the destruction of habitat, the natural area where an animal lives. Amphibians are very sensitive to changes in their habitat. If they cannot find the right conditions, they will not lay their eggs. These days, as wild areas are covered with houses, roads, farms, or factories, many kinds of amphibians are no longer laying eggs. For example, the arroyo toad (蟾蜍) of southern California will only lay its eggs on the sandy bottom of a slow-moving stream. There are very few streams left in southern California, and those streams are often muddy because of building projects. Not surprisingly, the arroyo toad is now in danger of extinction.
There are a number of other factors in amphibian decline. Pollution is one of them. In many industrial areas, air pollution has poisoned the rain, which then falls on ponds and kills the frogs and toads that live there. In farming areas, the heavy use of chemicals on crops has also killed off amphibians. Another factor is that air pollution has led to increased levels of ultraviolet (UV) light. This endangers amphibians, which seem to be especially sensitive to UV light. And finally, scientists have discovered a new disease that seems to be killing many species of amphibians in different parts of the world.
All these reasons for the disappearance of amphibians are also good reasons for more general concern. The destruction of land, the pollution of the air and the water, the changes in our atmosphere, the spread of diseases - these factors affect human beings, too. Amphibians are especially sensitive to environmental change. Perhaps they are like the canary (金丝雀) bird that coal miners once used to take down into the mines to detect poisonous gases. When the canary became iii or died, the miners knew that dangerous gases were near and their own lives were in danger.
选项
A、knowledge about fatal human diseases.
B、knowledge about air and water pollution.
C、a chance to discover new medicines.
D、an opportunity to detect poisonous gases.
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/w2Ld777K
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
SheworeagorgeousVictoriangownwhichwassaidtobeworththousandsofdollars.
HisnoveldepictsanambitiousAmerican.
InitiallythewriterdidnotwanttobuyahearingaidbecauseWhichofthefollowingisNOTtrueofCrystalEar?
GlucosecannotbeturnedintoenergyinthebodyToslowdowneyedamage,peoplewithdiabetesshouldtryto
LocalNewspapersinBritain1.Britainhasalargecirculation(发行量)ofthenationalnewspapers.TheDailyMirrorandTheDaily
WhichofthefollowingisNOTtrueofchronicdiseasesintheUS?Earlycancerscreeningcanhelpreducesignificantly
NewTechniquePromisesEarlierCancerDetectionAnewtechniquecouldrevolutionizetheearlydetectionofcancer,givingsuf
WHO:ManyChildren’sDeathsPreventableOverfivemillionchildrendieeachyearfromdisease,infectionsandaccidentsrelat
A.stayuptilltheearlyhoursofthemorningB.sleepenoughtobringmostrefreshmentC.rebuildmemoriesstoredduringthed
InBritainandmanyothercountriesappraisalisnowatoolofmanagement.
随机试题
张某2021年全年获得劳务报酬收入两次,分别为2000元,5000元。刘某两次劳务报酬所得应预扣预缴个人所得税为()元。
A.指压式B.执笔式C.全握式D.反挑式E.横握式切开范围广、用力较大的切开方式是
我国开展食盐氟化防龋的城市是
A.桑菊饮B.百合固金汤C.桑杏汤D.清金化痰汤E.银翘散某女,40岁,干咳少痰,痰中带血,午后咳甚,五心烦热,潮热盗汗。舌红少苔,脉细数。辨证为肺肾阴虚,治宜选用的方剂是()。
完全退火的目的是()。
根据《建设工程安全生产管理条例》,施工单位的()应当经建设行政主管部门或者其他有关部门考核合格后方可任职。
近年来,人大代表在百姓心中的分量越来越重。每年一次的人民代表大会,老百姓都能触摸到代表履职的“脉搏”,心系人民群众,热议国计民生,力推重要问题解决。这说明()。
前摄抑制是指先学习的材料对识记和回忆后学习的材料所产生的干扰作用:倒摄抑制是指后学习的材料对识记和回忆先学习的材料所产生的干扰作用。根据上述定义。以下哪项只包含倒摄抑制?
不经过频谱搬移直接使用原二进制电信号所固有的频率进行信号发送的数据传输形式被称为______。
A、Anengineroom.B、Abigkitchen.C、Agreattheatre.D、Ahighbuilding.C短文提到:“这种大型喷气式飞机的内部看上去更像一个大剧院。”故C正确。
最新回复
(
0
)