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
14
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] The passage mainly talks about ______.
选项
A、the effect of diseases
B、how to control the number of certain animals
C、the relationship between diseases and human population
D、different kinds of diseases
答案
A
解析
通览全文,文章谈了 disease 的作用,例如第一段"Disease can be one of the most powerful factors in checking population growth." 第二段"Apart from regulating population numbers in other species, disease has probably been the greatest factor in controlling the growth of the human population."
转载请注明原文地址:https://tihaiku.com/zcyy/3452095.html
相关试题推荐
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
Thoughitisamereonetothreepercentofthepopulation,theupperclass
随机试题
下列BIM应用管理模式中适用于工程全过程阶段的有()。A.设计主导管理模式 B
标准贯入试验规定穿心锤落距为()。A.70㎝ B.72㎝ C.76㎝
总配线架用图例表示为( )。
A.特拉唑嗪 B.依那普利 C.螺内酯 D.非洛地平 E.阿替洛尔原发性
对中国人民银行作出的具体行政行为不服的,可以向( )申请复议。A.中国银行业协
我国现阶段,不同国有企业的职工,付出同样的劳动,获得的劳动报酬会有所差别,这是因
一般来说,( )禀赋是国家经济发展和社会变迁过程中最稳定的因素。 A.自然
( )即了解这种实践模式,了解动作结构,各动作成分及其顺序等。该阶段学员主要是
A.硬区 B.缓冲区 C.主承托区 D.副承托区 E.边缘封闭区上下颌牙
属于病人道德义务的是 A.知情同意 B.支持医学科学发展 C.病人利益至上
最新回复
(
0
)