首页
登录
职称英语
Disease can be one of the most powerful factors in checking population growt
Disease can be one of the most powerful factors in checking population growt
游客
2024-02-15
52
管理
问题
Disease can be one of the most powerful factors in checking population growth. In crowded conditions where many individuals of a species are living close together, the spread of pathogens (病原体) from one individual to another, occurs readily. History shows many instances where human populations, crowded together in cities, have been almost wiped out by the rapid spread of disease. Modern orchard and forestry practice recognizes this fact and the close planting of trees of the same species is avoided. Mixed forests and orchards are the recognized procedure these days.
Apart from regulating population numbers in other species, disease has probably been the greatest factor in controlling the growth of the human population.
In the mid 14th century, the Black Death wiped out 25 million people in Europe alone, while as recently as 1918 over 21 million people died in a single year as a result of the influenza epidemic. The relative stability of the human population has been upset by advances in medical science. No longer does disease regulate human population growth in many parts of the world. Medical cures have prolonged life and upset the age structure of many populations, increasing the proportion of individuals in the reproductive age group.
The decrease in distribution and numbers of some species of native birds in New Zealand-the bellbird for example-has been attributed to disease rather than predation. Indeed, there are examples to show that disease has deliberately been used to control some animal populations. In Australia, for instance, the introduction of the myxomatosis (多发粘液瘤病) virus has drastically reduced the rabbit population in many areas, although increasing resistance to the disease is becoming apparent. Attempts to introduce myxomatosis into New Zealand as a means of rabbit population control have failed, mainly because the species of flea and mosquito that transmit the disease are absent in this country.
Research is currently being carried out to discover whether selected strains of virus can be used to control pathogenic bacteria that have developed a resistance to drugs. It is hoped that the virus will parasite (寄生) and kill the bacteria without harming the organism that the bacteria has infected. [br] What can we infer from the passage?
选项
A、Human’s future could be depended on advance in medical science.
B、We could introduce certain kind of disease to control the number of some species.
C、Human could control diseases.
D、Introduction of the myxomatosis could control rabbit population in the world.
答案
B
解析
见第四段,Australia 引进 myxomatosis 成功控制了 rabbit population, 这个例子告诉我们可以通过引进某种 disease 来控制某种物种的数量。
转载请注明原文地址:https://tihaiku.com/zcyy/3452094.html
相关试题推荐
Areallypowerfulspeakercan______thefeelingsoftheaudiencetothefevero
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
随机试题
[originaltext]Agoodmarriagemeansgrowingasacouplebutalsogrowingas
ManystudentsarerelyingonInternetandothertechnologiesfortheirlangu
WhaleFalls1.Thewhaleisakindofmarinemammal■【T1】_________size
SlashYourBills—6WaystoKeepMoreCash
患儿男,5岁。因发热2天,出现左上下肢无力1天入院。2天前无明显诱因发热,体温4
腰椎间盘突出症与腰椎管狭窄症临床症状的主要不同之处在于A.腰痛及下肢放射痛的程度
在住宅项目价格制定过程中,核心均价的确定有很多种方法,包括( )。A.市场提取
我国房地产经纪行业中较早发展起来,且市场参与度尚不够高的房地产经纪机构是( )
女,26岁,足月分娩后12个月后出现持续的阴道不规则流血,血β-hCG持续高水平
在编制财务报表前,需要完成下列工作中,正确的是()。A、严格审核会计账簿记录和有
最新回复
(
0
)