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
2018-04-17
43
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(跳人) 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 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://www.kaotiyun.com/show/taiC777K
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
Nowadaysmostpeopledecidequite【61】whatkindofworktheywoulddo.WhenIwasatschool,wehadtochoose【62】whenwewerefif
OneBritishschoolisfindingthatallowingchildrentolistentomusicoreventohavetheTVonwhilestudyingishelpingimpr
OneBritishschoolisfindingthatallowingchildrentolistentomusicoreventohavetheTVonwhilestudyingishelpingimpr
Onlyoneanimalcanwalk200mileswithoutstoppingoncetorest.Itwouldtakeapersontwodaysandtwonightstowalkthisfa
StudentA:MayIuseyourcomputerthisafternoon?StudentB:I’msorry,butIhavetofinishtypingthistermpapertoday.Stude
Passer-by:______Localresident:Sure.It’sonEhnStreet:betweenEleventhandTwelfthAvenue.Passer-by:Thankyou.
Animportantbusinessmanwasaskedtogiveatwenty-minutespeechinanothercity.Hewastoobusytowriteithimself,soheas
Noformofthinkingismoreinterestingthandreams."Brainwave"machineshaveshownthatdreamslastonlytwototenseconds,
Theurbanenvironmenthastoofferasmanyrecreationactivitiesaspossible,andthedesignofthesehastobesuchthatmoreo
Aspartofanongoingcampaignagainstpolyvinylchloride(聚氯乙烯),aVirginia-basedenvironmentaladvocacygrouptodaycalledonm
随机试题
内幕信息的构成要素不包括()。
计算.
简述孕激素的生理作用。
患者,男性,46岁。因黑便,伴呕吐3日入院,病前有10余年胃溃疡病史,查体:贫血貌,皮肤无黄染,左锁骨上内侧可触及质硬而固定的淋巴结。入院后第3天,患者突然出现呕血,呕出暗红色血液700ml,此时,对该患者要采取的首要护理措施是
急性心肌梗死24小时内应禁用的药物是
通过观察、实验和测验等方法考察心理活动过程及其效率的指标,被称为()。
下图是植物细胞有丝分裂过程中染色体形态示意图,以下叙述正确的是()。
近代形而上学唯物主义()。
行为人甲为顺利抢劫被害人财物,直接杀死被害人;行为人乙在抢劫过程中,遭到被害人强烈反抗,而杀死被害人。对甲、乙两人的行为应认定为()。
下列描述中,错误的是()。
最新回复
(
0
)