首页
登录
职称英语
Marine ecosystems certainly have less permanence than terrestrial ecosystems
Marine ecosystems certainly have less permanence than terrestrial ecosystems
游客
2025-02-19
26
管理
问题
Marine ecosystems certainly have less permanence than terrestrial ecosystems. Ashore, ecologists are not confronted with shifting ecological discontinuities, or with changes in the characteristic conditions of individual ecosystems, because, unless man intervenes, the tree line on a mountain or the passage between grassland and savannah remains approximately static over a human lifetime. It is only on the millennial scale that such boundaries migrate significantly, or that characteristic regional ecosystems disappear. Urban sprawl, deforestation, overgrazing, and intensive agriculture are accomplishing in a few decades what nature cannily do in centuries, but that sad fact does not alter the argument. Although the human population explosion can produce pressures that rapidly shift ecological boundaries and modify ecosystems ashore, it is paradoxically more difficult directly to modify the average locations of the ephemeral and shifting
ecological boundaries of the sea
. We can accomplish this only indirectly by atmospheric modification, resulting in a changed global climate and a shifted ocean circulation. [br] The primary purpose of the passage is to
选项
A、examine differences in the threats faced by marine and terrestrial ecosystems.
B、explain how human intervention has affected marine and terrestrial ecosystems.
C、discuss a distinguishing feature of marine ecosystems
D、present a debate regarding the causes of marine ecosystem impermanence
E、discuss certain consequences of marine ecosystem impermanence
答案
C
解析
本文的主旨就是讨论海洋生态系统的不持久性,所以选项C正确。A项本文确实可以看作将两种生态系统做对比,但是对比的是持久性而非threats。B项文章通过将人类如何影响了陆地和海洋生态系统来说明海洋生态系统不持久,因此选项B只是文章得出最终结论的过程,属于细节。D项文中未提及a debate,文中只有作者的观点,不存在辩论。E项文章没提海洋生态系统不持久所带来的结果是什么。
转载请注明原文地址:http://tihaiku.com/zcyy/3964103.html
相关试题推荐
Marineecosystemscertainlyhavelesspermanencethanterrestrialecosystems
Ourterrestrialfoodsupplycomesfromecosystemstransformedtoproduceaf
MarinearchaeologistsrecentlydiscoveredunderwaterinanancientMediterra
Thecrustaceansknownasharpacticoidsareverywidespreadinmarinesedimen
Whatisthewriter’sconclusionconcerningthedeclineofmarineresources?A、The
Timekeeper:InventionofMarine
Timekeeper:InventionofMarine
Timekeeper:InventionofMarine
Timekeeper:InventionofMarine
Timekeeper:InventionofMarine
随机试题
Allitcanreallydoistopointresearchersintherightdirectionforfurther
"ResourcesandIndustrialisminCanada"Whilethemuch-anticipatedexpansion
北京师范大学学制研究小组于1981年在其附属中小学开始进行的学制实验是()。A.
沥青材料老化后,其质量将()。A.减小 B.增加 C.不变 D.有的减小
材料一:在全面实施素质教育的要求下,怎样评价学生的优、良、中、差呢?为此,某教师
有的学生在初学英语单词时,常常在单词旁边标注汉字,如把“best”标注成“百斯特
在前期建筑策划中应考虑的相关因素包括( )。A.建筑造价 B.建筑法规 C
下列选项中,会对独立性产生不利影响的情形是( )。A.为审计客户提供设计或操作与
采用相关图法分析工程质量时,散布点形成一团或平行于x轴的直线带,说明两变量之间的
4个月女婴,冬季出生,足月顺产,单纯牛奶喂养,未添加辅食。近半个月来较烦躁,夜哭
最新回复
(
0
)