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
外语
A、Collect ash tree seeds for experiment. B、Preserve the healthy ash tree seeds. C、Set up a new seed bank for research. D、Develop
A、Collect ash tree seeds for experiment. B、Preserve the healthy ash tree seeds. C、Set up a new seed bank for research. D、Develop
admin
2019-03-17
52
问题
A beetle invasion in the United States has killed at least twenty million ash trees. The invasion of the emerald ash borer was first discovered near Detroit, Michigan, in 2002. Experts believe the small green insects arrived in the 1990’s in shipments of goods from China.
[16] The emerald ash borer has destroyed trees in the Midwest and as far East in the United States as Maryland. [17] The insects have also spread as far north as Ontario, Canada.
Ash trees can resist many diseases. But they cannot resist the emerald ash borer. [18-1] It lays eggs on the bark.The young larva drill into and feed on the inner bark. This harms the ability of the tree to transport water and nutrition.
In some places, farmers are using “detection trees”. They have an area where bark has been cut away. The area circles the tree. [18-2] The process weakens the tree. It makes them easier targets for borers, and shows if the insects are nearby.
Efforts to stop the spread of the emerald ash borer include cutting down affected trees. There are worries that the ash tree might disappear unless the invasion is controlled. To prepare for such a possibility, a government laboratory is asking people to send in the seeds from ash trees. [19] It examines and X-rays the seeds to make sure there are no living borer fertilized eggs.Only the best seeds are remained and then sent for storage in a seed bank. There, they are dried and frozen. Should the seeds ever be needed, the hope is that scientists might someday develop an ash tree that could resist the little green attackers.
1.What’s the speaker mainly talking about?
2.How far do the insects spread northward?
3.Why is part of the bark cut away?
4.What is the government laboratory trying to do?
选项
A、Collect ash tree seeds for experiment.
B、Preserve the healthy ash tree seeds.
C、Set up a new seed bank for research.
D、Develop a new breed of ash tree.
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/8pH7777K
0
大学英语六级
相关试题推荐
A、Peoplearebomwiththem.B、Theyareinvalid.C、Peoplecannotgetridofthem.D、Theycandestroypeople’sambitions.D
A、Studentsstudyinginathree-yearcollege.B、Studentswhosefathersarefarmers.C、Studentsmajoringinagriculture.D、Student
CheatinginGCSEandA-Levelsbypupils,teachersandevenschoolexamcentresrosemarkedlylastyear,withevermoresophistic
NurseHomeVisits:ABoostforLow-IncomeParents[A]NursehomevisitorTammyBallardhashadsomememorableexperiencesinclo
A、Financialsecuritymattersalottothem.B、Theychaseeverymarkofthestockmarket.C、They’renotsoconcernedwithmoney.
Peoplehavewonderedforalongtimehowtheirpersonalitiesandbehaviorsareformed.Itisnoteasytoexplainwhyoneperson
A、Namesoftherecommendedbooks.B、Thenameandnumberofherprofessor.C、Aletterofrecommendationfromthesupervisor.D、Th
Inthethrillingprogressiveyearsoftheearly20thcentury,fewthingsweremoreattractivethanthepromiseofscientifickno
Englishistheleadinginternationallanguage.Indifferentcountriesaroundtheglobe,Englishisacquiredasthemothertongue
Researchonanimalintelligencealwaysmakesuswonderjusthowsmarthumansare.Considerthefruit-flyexperimentsdescribedb
随机试题
自招标文件出售之日起至()之日止,最短不得少于5个工作日。
保险公司、医院、大学、汽车制造商所处的环境属于低一中程度不确定性的环境类型。()
采用酸碱指示剂原理的尿试带检测项目是
女,68岁,突发上腹部阵发性绞痛2小时,短时间内出现寒战、高热,小便呈浓茶样,随后嗜睡。查体:T39.6℃,P128次/分,R30次/分,BP80/50mmHg,神志不清,躁动,巩膜黄染,右上腹肌紧张并有压痛和反跳痛。急症手术最有效的手术方式为
合同控制措施中,不包括()。
某住宅的屋面和外墙外保温系统均采用燃烧性能为B1级的保温材料,外墙和屋面分隔处应设置不燃材料制作的防火隔离带,其宽度不得小于()mm。
赵某使用银行卡支付宾馆住宿费1万元。根据银行卡业务管理规定,银行办理该银行卡收单业务收取的结算手续费应不得低于( )元。
甲公司为增值税一般纳税人,主要从事大型机械设备制造和销售业务,2020年10月有关经营情况如下:(1)购入原材料取得增值税专用发票注明税额39万元;进口检测仪器取得海关进口增值税专用缴款书注明税额26万元。(2)报销销售人员国内差旅费,取得网约车费增值税电
实事求是、群众路线、独立自主是()。
“明月出天山,苍茫云海间”是李白的著名诗句,我们根据该诗句可以推断:
最新回复
(
0
)