首页
登录
职称英语
All along me chain of biological evolution, the extinction of species appears
All along me chain of biological evolution, the extinction of species appears
游客
2023-12-20
9
管理
问题
All along me chain of biological evolution, the extinction of species appears to have been a stage in the process of adapting genetic lineages to changing environmental conditions. Although some catestrophic extinction occurred naturally, producing total loss of a genetic line, such catastrophes were comparatively rate. In modern times, however, human activities have altered the fundamental nature of this process, resulting in nearly total genetic losses.
It is not difficult to gain general agreement that man -induced increases in the endangerment and extinction of wildlife whether due to habitat alteration or loss, pollution, insufficiently regulated hunting, or other factors are undesirable. It is, however, more difficult to obtain consensus when consideration is given to the economic costs of correcting such trends, including natural habitat preservation, regulation of pesticides and other toxic substances, and wildlife and park management. Endangered species often are, in effect, competitors with humans for habitat and other resources which also provide other kinds of human use and need.
Measures needed to protect endangered species vary considerably in difficulty and cost. Of the approximately 400 inverterate species which at present appear to be threatened, for example, about one third could probably be restored by such inexpensive means as modifying the boundaries of designated natural are as, acquiring and protecting caves and other small areas which contain the particular species, and additional management ’of parks and refuges.
Another one - third of the endangered lower animal species are threatened principally by water pollution and could be protected by improved control, particularly of five southern rivers.
The remaining one - third of the 400 endangered shellfish species would be considerably more difficult to protect. These are threatened by complex factors, such as overcollecting, channelization, highway and housing development, clams introduced species such as the Asian snail, dredging, quarry washing, poor erosion control, and lowering of water table.
The identification of threatened species and other significant wildlife trends must precede any corrective measures, and our knowledge base for making such identification is deficient in many respects. Our present lists of threatened species and subspecies are known to be incomplete, except in those geographical areas which contain habitats of species that have important commercial or sports harvest value. [br] It can be inferred from the passage that studies of endangered species ______.
选项
A、have revealed little of importance to improve wildlife preservation
B、are more likely to be carded out when a financially concerned interest group is involved
C、sometimes endanger the very species they hope to protect
D、show that endangered species can never be saved except at great cost
答案
B
解析
文章最后一句表明由于商业或捕猎的原因,这些地方的某些物种即全部灭绝,在其它地方情况则会好一些,这种对比表明这些研究要不是对一部分人有收益,就不会展开。
转载请注明原文地址:https://www.tihaiku.com/zcyy/3290097.html
相关试题推荐
Indozensofyears,therearemorecasesoftheinvasionofalienspeciespartly
Indozensofyears,therearemorecasesoftheinvasionofalienspeciespartly
Indozensofyears,therearemorecasesoftheinvasionofalienspeciespartly
Thedigitalrevolutioninconsumerelectronics,includingpersonalcomputerg
Thedigitalrevolutioninconsumerelectronics,includingpersonalcomputerg
AftertheAmericanRevolution,_____becamethefirstcapitaloftheUnitedStat
Theso-called"GloriousRevolution"of1688tookplacein_____.A、FranceB、Americ
Likeallanimalspecies,plantspeciesmustspreadtheiroffspringtosuitabl
Likeallanimalspecies,plantspeciesmustspreadtheiroffspringtosuitabl
Likeallanimalspecies,plantspeciesmustspreadtheiroffspringtosuitabl
随机试题
Thepresentparticiple(现在分词)in"We’rehavingarippinggoodtime"isusedtom
TrustMe,I’maRobot[A]Withrobotsnowemergingfromt
如果李生喜欢表演,那么他报考戏剧学院,如果他不喜欢表演,那么他可以成为戏剧理论家
描述GDP与消费的关系适宜的图形是()。A.饼图 B.散点图 C.直方图
()是商业银行和其利益相关群体保持密切联系的纽带。A.媒体 B.股东大会 C
从合同的计价方式看,FID、I1999年版《施工合同条件》(新红皮书)是()合同
中国人民抗日战争积累了丰富的经验,其中一条经验便是中国人民战胜一切艰难困苦,实现
儿童脑的发展大约在4~20岁之间存在两个显著的加速时期,即( )A.5~6岁左
公安机关要接受同级党委的( )的领导。A.组织部门 B.政法委员会 C.宣
关于架空线路的地线支架高度,下列哪些表述是正确的?()A.满足雷击档距中央地线
最新回复
(
0
)