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
15
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
[originaltext]M:Sowhatwouldyourecommend,whatpracticalthingswouldyour
YoungPeopleShouldPursueLong-term,RealisticGoalsThemodernsociety
Theboyworeajacketthatwas______largeforhim.A、toomuchB、muchtooC、grea
TheredcrossonthenationalflagoftheU.K.standsforA、patronsaintofScotl
保持职业审慎是内部审计师的一项技能,下列选项中,属于内部审计师应该保持审慎性的内
隧道渗漏水大部分与施工缝和沉降缝有关。()
白芷的功效是A.祛风解表,消肿排脓B.发汗解表,温中止呕,温肺止咳C.发汗解表,
患者女,25岁。右下颌下区无痛性肿块发现10余年。肿块生长缓慢,压缩感(+),体
下列管理模式的特征中,属于Partnering模式特征的是()。A.承包商承担大
(2017年真题)对于人员密集场所,建设单位不需要向公安机关消防机构申请消防设计
最新回复
(
0
)