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
专升本
The "balance of nature" is not an empty phrase. Nature provides a population to occupy a suitable environment and cuts down surp
The "balance of nature" is not an empty phrase. Nature provides a population to occupy a suitable environment and cuts down surp
admin
2017-09-04
27
问题
The "balance of nature" is not an empty phrase. Nature provides a population to occupy a suitable environment and cuts down surplus population to fit the available food supply. One means of reducing surplus population is predators (食肉动物) ; others are parasites (寄生虫) and diseases. Also, population density produces nervous disorders and even drives animals to mass migrations, like the lemmings (旅鼠) of Norway who plunge into (跳入) the sea.
That predators populations increase to control other animals has long been known. Many years ago, the Hudson’s Bay Company records revealed that the fox population went up and down about a year after the rabbit population had gone up and down.
Sometimes a situation occurs in which the predators population is reduced to a level below that which nature can readily replace. On Valcour Island in Lake Champlain ( New York) , a costly campaign resulted in the elimination of predatory animals only to have birds and small animals—including grouse (松鸡) and hares, popular game(猎物)—increase for four years afterward. Then lacking predator control, nature resorted to diseases to cut down these populations.
Jamaica had an example of nature’s persistence in providing animals for existing habits. Sugar planters, about 75 years ago, imported mongooses to control rats. The mongooses killed off the rats and, with plentiful food, multiplied. Rats became scarce and the mongooses ate lambs, kids, puppies(小狗) , and wildlife. Eventually, food became scarce and the mongoose’s population declined.
When the mongooses in Jamaica killed off the rats, they________.
选项
A、quickly died for lack of food
B、attacked humans
C、became problems themselves
D、ate the sugar crop
答案
C
解析
第四段结尾说到“The mongooses killed off the rats and,with plentiful food,multiplied.Rats became scarce and the mongooses ate lambs,kids,puppies(小狗)and wildlife.”可推知mongooses杀了rats后,它们自身生存也成了问题。故选C。
转载请注明原文地址:https://kaotiyun.com/show/GYiC777K
本试题收录于:
英语题库成考专升本分类
0
英语
成考专升本
相关试题推荐
Readthefollowingdialogueandtrytofillupthegapswithproperwords,phrases,orsentences.SalesAssoc:Hi,areyoub
Workingonanewspaperisaverybusyjob.Manynewspapers【21】eachday,andtheyhaveto【22】peoplewithallthelatestnews.The
Howoftenonehearschildrenwishingtheyweregrownup,andoldpeoplewishingtheywereyoungagain.Eachagehasitspleasure
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompletethefollowingdialogsbyblackeningthecorrespon
Pickouttheappropriateexpressionsfromtheeightchoicesbelowandcompletethefollowingdialogsbyblackeningthecorrespon
EverycultureandeverycountryintheworldcelebratesNewYear,butnoteveryonedoesitthesameway.ThecountriesinNorth
Shopassistant:Goodmorning.CanIhelpyon?Customer:______.I’mjustlookingaround.
TodaytheofficiallanguageoftheUnitedStatesandmostofCanadaisEnglish.However,Frenchalmostbecametheofficiallangu
Noformofthinkingismoreinterestingthandreams."Brainwave"machineshaveshownthatdreamslastonlytwototenseconds,
随机试题
美国人有许多风俗习惯在陌生人看来是颇费解的。
A.四海舒郁丸B.海藻玉壶汤C.栀子清肝汤合消瘰丸D.滋水清肝饮E.天王补心丹患者颈前肿,质较软,伴心悸不宁,少寐,易出汗,手抖,目眩,倦怠乏力,舌质红,舌体颤动,脉弦细数,治疗宜选
A.越婢加术汤B.麻黄连翘赤小豆汤合五味消毒饮C.五皮饮合胃苓汤D.实脾饮E.疏凿饮子治疗水肿风水泛滥证,应首选()
下列表述正确的是___________。
个人征信异议产生的主要原因有()。
根据《票据法》的规定,下列选项中汇票的绝对应记载事项有()。
企业在发展期应提高()管理人员的管理能力。使之适应企业的要求。
某科学家将1个带有标记的细胞放入正常的培养基中培养,细胞每隔20分钟便分裂为2个细胞,且其中只有1个细胞是带有标记的,则2个小时后有标记的细胞所占的比重为()。
软件测试是软件质量保证的重要手段,其任务可归纳为:预防软件发生错误、发现改正程序错误和______。
在窗体中添加一个命令按钮(名为Command1)和一个文本框(名为text1),然后编写如下事件过程:打开窗体运行后,单击命令按钮,文本框中显示的内容是()。
最新回复
(
0
)