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
A、Pollution of the environment. B、A new generation of pest killers. C、Over-killing by hunters. D、Destruction of their natural ho
A、Pollution of the environment. B、A new generation of pest killers. C、Over-killing by hunters. D、Destruction of their natural ho
admin
2012-12-13
34
问题
America’s national symbol, the bald eagle, almost went extinct 20 years ago. But it has made a comeback. In fact, the U. S. Fish and Wildlife Service is considering the possibility of taking it off the endangered-species list.
Once, more than 50,000 pairs of bald eagles nested across the country. But by 1960, that number had fallen below 400.
The chief killer was the widely used DDT. Fish soaked up DDT, died, and were washed up on shores, where bald eagles feasted on them. DDT prevented eagle eggshells from thickening. The shells became so thin that they shattered before the babies hatched.
Fortunately, in 1972, a law was passed to ban DDT, which saved the bald eagle from total wipeout. And since then, wildlife biologists have reintroduced bald eagles from Canada to America. The result was that last year U. S. birdwatchers counted 11, 610 bald eagles in the country.
If it were dropped from the endangered list, the bald eagle would still be a " threatened species.” That means the bird would continue to get the same protection - no hunting allowed, and no disturbing of nests.
But bald eagles still face tough times. The destruction of their natural homes could be the next DDT causing eagle numbers to drop quickly.
选项
A、Pollution of the environment.
B、A new generation of pest killers.
C、Over-killing by hunters.
D、Destruction of their natural homes.
答案
D
解析
转载请注明原文地址:https://jikaoti.com/ti/UekFFFFM
0
大学英语六级
相关试题推荐
Manyuniversitycoursesarenotreally______totheneedsofstudentsortheirfutureemployers.
The______explanationsthattheresponsiblegaveforthehugelossinforeigntradecouldn’texempthimfromthepunishmentof
InChina,allthestudentsbetweentheagesof7and16orsomustreceivenine-year______education.
Thiscanresultduetoreductionsinovermanningandimprovementsinothertypesof______managementprocedures.
Thereisa________differenceinmeaningbetweenthewordssurroundingsandenvironment.
A、Professorandstudent.B、Bossandemployee.C、Interviewerandinterviewee.D、Presidentandadviser.C选项均是一对身份相对的词表明,本题考查对话双方的关
A、HeadmiresJean’sstraightforwardness.B、HethinksDr.Browndeservesthepraise.C、HebelievesJeanwasrudetoDr.Brown.D、
HowGeniusesWorkIn1905,AlbertEinsteindevelopedthetheoryofspecialrelativity.Healsoprovedthatatomsexistandf
A、TheydrankaspecialbeveragemadefromJapaneseherbs.B、Theyhaduncookedfishthenightbeforethegame.C、Theyhadamassa
A、TellMaryaboutthering.B、CallMarybeforeeachmeeting.C、TellMaryaboutthevolunteermeeting.D、KeepMarywaitingforhi
随机试题
理论界通常将内部控制的发展过程分为4个阶段,其中_______是以账目之间的相互核对为主要内容并实施岗位分离()
随着DSA技术的发展,对于运动部位的DSA成像以及DSA成像过程中X线管与检测器同步运动而得到系列减影像,已成了事实。所以,将DSA成像过程中,X线管、人体和检测器规律运动的情况下,而获得DSA图像的方式,称之为动态DS
下列关于项目特点的表述,错误的是()。
消费者因产品缺陷遭受人身、财产伤害的,可以向()要求赔偿。
当前和今后一个时期国际形势发展的基本态势是()。①总体和平、局部战争;②总体缓和、局部紧张;③总体封闭、局部开放;④总体稳定、局部动荡。
西方社会两大法系的差别有()。
简述我国合同法对提存的规定。
结合【】和自顶向下结构化方法的思想构成了现在大部分信息系统开发方法的理论基础,如结构化生命周期方法。
Howmuchdothethingscost?
Forthispart,youareallowed30minutestowriteashortessayentitledCriticism.Youshouldwriteatleast120wordsfollowi
最新回复
(
0
)