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
Since there is such an abundance of food in the sea, it is understandable that some of the efficient, highly adaptable, warm-blo
Since there is such an abundance of food in the sea, it is understandable that some of the efficient, highly adaptable, warm-blo
admin
2013-02-16
73
问题
Since there is such an abundance of food in the sea, it is understandable that some of the efficient, highly adaptable, warm-blooded mammals that evolved on land should have returned to the sea. Those that did do that have flourished. Within about 50 million years—no time at all, geologically speaking —one of the four kinds of mammals that has returned to a marine environment has developed into the largest of all animal forms, the whale. A second kind, the seal, has produced what is probably the greatest population of large carnivorous mammals on Earth. This suggests that these "top dogs" of the ocean are prospering and multiplying. However, such has not been the case, at least not for the last 150 years. Trouble has closed in on these mammals in the form of equally warm-blooded and even more efficient and adaptable predators, humans. At sea, as on land, humans have now positioned themselves on top of the whole great pyramid of life, and they have caused serious problems for the mammals of the sea.
There is a simple reason for this. Marine mammals have the misfortune to be swimming aggregates of commodities that humans want: fur, oil, and meat. Even so, they might not be so vulnerable to human depredation if they did not, like humans, reproduce so slowly. Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species. But the slow-breeding mammals of the sea have been all but wiped out by humans seeking to satisfy their wants and whims.
It can be inferred from the passage that during the last 150 years humans have ______.
选项
A、constructed submarines
B、learned how to swim
C、threatened the existence of some marine mammals
D、begun to harvest certain plants from the ocean as food
答案
C
解析
根据文章第一段最后四句可知,这些海洋中的“大哥大”们人丁兴旺,一派繁荣景象。但事实并非如此,至少在过去150年来是这样。同样是暖血动物而且效率更高、适应性更强的捕食者——人类,已成为这些哺乳动物日益迫近的威胁。和在陆地一样,人类在海洋也已处在巨大的生物金字塔的最顶端,成为所有生物的主宰,给海洋哺乳动物带来严重威胁。据此判断,答案是C。
转载请注明原文地址:https://kaotiyun.com/show/qbmO777K
0
考博英语
相关试题推荐
Whatdotheextraordinarilysuccessfulcompanieshaveincommon?Tofindout,welookedforcorrelations.Weknowthatcorre
Withacandleinhand,hecarefully_____thenarrowstairstohisbedroom.
Tounderstandtilemarketingconcept,itisonlynecessarytounderstandthedifferencebetweenmarketingandselling.Nottoom
Whenaninventionismade,theinventorhasthreepossible【C1】______ofactionopentohim:hecangivetheinventiontofilew
Someweeksago,ridinginacabfromBostontoCambridge,mydriverturnedandaskedmewhatIdidforaliving."TeachEnglish,
Forthispart,youarerequiredtowriteacompositionofatleast250wordsaccordingtothefollowinginstruction."Somepeopl
Theneedforsolarelectricityisclear.Itissafe,ecologicallysound,efficient,continuouslyavailable,andishasnomoving
Don’tcallhimjustacollegeprofessor.Internetentrepreneur,TVpersonality,advisertopresidents,andfriendtotherichan
MywritinginmylateteensandearlyadulthoodwasfashionedaftertheU.S.shortstoriesandpoetrytaughtinthehighschools
PriscillaOuchida’s"energy-efficient"houseturnedouttobeahorribledream.Whensheandherengineerhusbandmarriedafew
随机试题
分析缺陷出现和数量变化趋势的规律,以便为判断该缺陷属人为责任、工艺欠周详还是条件变化提供有力的依据。()
乙型脑炎的主要传播媒介是
缺隙保持器的适应证是乳牙早失,牙冠上覆盖有较厚的骨组织,恒牙胚牙根形成不足
患者。男性。54岁。既往史不详。突然发生呼吸困难,满肺哮鸣音,心率110次/min,心脏听不清有无杂音。宜首选的药物是
如图所示,托架承受均布荷载q作用,设撑杆AB为细长压杆,其两端铰支,已知材料弹性模量为E,截面惯性矩为I,当均布荷载q达到()时,杆AB处于临界状态。
支顶危石、悬岩,其砌体基础应置于完整、稳固的岩体上,并()。
()与银行间债券市场共同构成我国的债券市场。
(2013年卷一第22题)在中国设有办事处的美国某公司欲就其一项发明创造在中国申请专利。该公司可以通过下列哪种方式提交其申请?
教师教学应该以学生的认知发展水平和已有的经验为基础,面向全体学生,注重启发式__________和__________.
乙建筑公司向甲建材公司发出传真,表示“急需0号水泥100吨”。甲公司收到传真后,立即回电表示没问题,并开始安排货源。但三日后,当甲公司询问如何发货时,乙公司表示已经购得,不再需要该种水泥。双方发生争议,甲公司诉至法院。[中财2014年研]根据上述
最新回复
(
0
)