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
自考
Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition,man can catch th
Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition,man can catch th
admin
2011-01-31
76
问题
Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition,man can catch the disease from animals. In fact,a great number of wild birds seem to carry the virus without showing any evidence of illness. Some scientists conclude that a large family of influenza viruses may have evolved in the bird kingdom,a group that has been on the earth 100 million years and is able to carry the virus without contracting the disease. These are even convincing evidence to show that virus strains are transmitted from place to place and from continent to continent by migrating birds.
It is known that two influenza viruses can recombine when both are present in an animal at the same time. The result of such recombinations is a great variety of strains constraining different H and N spikes. This raises the possibility that a human influenza virus can recombine with an influenza virus form a lower animal to produce an entirely new spike.
Research is underway to determine if that is the way that major new strains come into being. Another possibility is that two animal influenza strains may recombine in a pig,for example,to produce a new strain which is transmitted to man.
New strains of viruses are transmitted to man by______.
选项
A、a type of pig
B、diseased lower animals
C、a group of migrating birds
D、a variety of means
答案
B
解析
见第二段最后一句话。
转载请注明原文地址:https://kaotiyun.com/show/zCAR777K
本试题收录于:
英语(二)题库公共课分类
0
英语(二)
公共课
相关试题推荐
SomepeoplemightthinkthatFather’sDaywasestablishedasaholidaytohelpgreetingcardcompaniessellmorecards.However,
SomepeoplemightthinkthatFather’sDaywasestablishedasaholidaytohelpgreetingcardcompaniessellmorecards.However,
ManypeoplethinkNewYorkisanoisycity.Infact,scientistswhostudynoisesaythattheaveragenoiselevelinNewYorkis7
ManypeoplethinkNewYorkisanoisycity.Infact,scientistswhostudynoisesaythattheaveragenoiselevelinNewYorkis7
ManypeoplethinkNewYorkisanoisycity.Infact,scientistswhostudynoisesaythattheaveragenoiselevelinNewYorkis7
Everybodygetssick.Diseaseandinjurymakeussufferthroughoutourlivesuntil,finally,someattackonthebodybringsour
Everybodygetssick.Diseaseandinjurymakeussufferthroughoutourlivesuntil,finally,someattackonthebodybringsour
An______(occupation)diseaseisonethatyoucangetifyouaredoingaparticularjob.
随机试题
Iftherewerenoexaminations,weshouldhave______atschool.
膀胱结核行膀胱扩大术前至少应接受几周的抗结核药物治疗
治疗胃癌气血亏虚型,应首选
A.2~3dB.3~7dC.7~10dD.10~14dE.2~3周生理性黄疸消退的时间()。
不计数额,下列哪一选项构成侵占罪?
某啤酒生产线设备安装工程项目,施工项目部在各工程正式施工开始前,对各项准备工作及影响质量的各因素和有关方面进行了质量控制。施工项目经理部为了确保工程项目质量符合设计意图和国家规范、标准的要求,采用PD—CA循环方法对该工程进行质量控制。
建设工程项目总进度目标论证的工作包括:(1)项目结构分析;(2)编制各层进度计划;(3)进度计划系统的结构分析;(4)项目的工作编码。其正确的工作顺序是()。[2013年真题]
生产经营单位对从业人员进行安全生产教育和培训的内容包括()。
被称为“国际会议之都”的城市是()。
多路复用(Multiplexing,也称多路复接)是通信中常用的技术,在不同的应用场合中可以采用不同的多路复用方式,如:(23):6芯光缆就是采用这种方式;(24):GSM通信中采用此方式;(25):用此方式60路话音可复用一个超群(Supergro
最新回复
(
0
)