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
Scientists have long believed one way to stop the Earth’s atmosphere from warming is by planting more trees. The idea is that mo
Scientists have long believed one way to stop the Earth’s atmosphere from warming is by planting more trees. The idea is that mo
admin
2009-04-23
58
问题
Scientists have long believed one way to stop the Earth’s atmosphere from warming is by planting more trees. The idea is that more trees will take in or absorb some of the carbon dioxide in the atmosphere. Carbon dioxide is a gas released by cars, factories and other human activities. The gas traps heat in the Earth’s atmosphere, which warms the planet. However, two new studies have found that trees may not be as helpful in reducing carbon dioxide as had been thought.
The first study was done at Duke University in Durham, North Carolina. Researchers pumped extra carbon dioxide into a test area where pine trees were growing. The trees grew thirty-four percent faster during the first three years. However, in time, the trees slowed to about their normal growth rate. The scientists say this is because trees need other nutrients, such as nitrogen.
In the second study, researchers from Duke and Bowdoin College in Brunswick, Maine examined the soil around trees. They discovered that as the leaves broke down into the soil, all the carbon was not trapped in the soil. Much of it was released into the atmosphere as carbon dioxide.
The findings of the two studies were published last month in Nature magazine. They suggest there is limited value in planting trees to reduce the carbon dioxide pollution in the atmosphere.
Forest planting has been a part of negotiations on a world agreement to reduce greenhouse gases that scientists believe cause global warming. The United States, Canada, Japan and some other industrial countries have supported the idea. But this new research suggests the idea is not as effective as environmental activists had thought. Scientist Ram Oren of Duke University led the study on tree growth. He says that earlier estimates on the ability of forests to absorb carbon dioxide were overly hopeful.
Some scientists not involved in the studies say the research provides some of the first evidence on how trees react to carbon dioxide. Other scientists say the research disputes a belief among some coal and power companies. The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming. Instead, they say it will increase forests and other plants.
选项
A、Introduce some new ideas about the relationship between trees and carbon dioxide.
B、Introduce recent condition of global industrial pollution.
C、Call on people to plant more trees to reduce greenhouse gases.
D、Point out that power companies should be responsible for the rising levels of carbon dioxide.
答案
A
解析
主题题。B,D均与本文无关;C则由于实验显示树木吸收并不那么有效,因此从本文观点来看正好错误。
转载请注明原文地址:https://kaotiyun.com/show/JnpK777K
0
大学英语六级
相关试题推荐
Theholidaysarethemostwastefultimeoftheyear.Theamountofwasteproducedincreasesbymorethan25%fromThanksgivingt
Lifeexpectancyisrisinginmuchoftheworld.Butdoctorsareseeinganothertrendthatisdisturbing.Somepeoplearechoosin
Inthemeetingheldlastnightthevicepresidentrefusedtomakeanycommentonthematterbeforemakingdueinvestigation.
Bytheendofthisyear,he______inthisfactoryforasmanyasthirtyyears.
Frank’sfather,______worksinaforeigntradecompany,alwaysgoesonabusinesstrip.
DearSir,MickeyMouseisoneoftheleadingcompaniesintoyretailinglocatedintheUK.Wehaveoutletsthroughoutthewh
Scientistsfindthathard-workingpeoplelivemuchlongerthanaveragemenandwomen.Careerwomenarehealthierthanhousewives
Scientistsfindthathard-workingpeoplelivemuchlongerthanaveragemenandwomen.Careerwomenarehealthierthanhousewives
Scientistsfindthathard-workingpeoplelivemuchlongerthanaveragemenandwomen.Careerwomenarehealthierthanhousewives
随机试题
简述设计人员参加交底会议的工作内容。
血管造影时引起的感染包括
患者晨起发现刷牙时右侧口角漏水,照镜发现右侧口角下垂、眼睑闭合不全。就诊后查体:右侧口腔颊、舌及口底黏膜较对侧干燥,无光泽;右侧舌前2/3味觉较对侧迟钝,听力较对侧差,Schirmer试验发现右侧泪液分泌少于对侧。该患者面神经损害的部位可能在
患者脘腹痞满疼痛,下痢赤白,里急后重,舌苔黄腻,脉沉实。治疗应选用
(2005年考试真题)纳税人享受减税、免税待遇的,在减税、免税期间应当按照规定办理纳税申报。()
,4,()
美国科学家的一份报告指出:滨海湿地生态系统每公顷每年创造的综合价值达4025美元,相当于同等面积的热带雨林的2倍,或其他森林的13倍,或草地的17倍,或农田的44倍!对句中“价值”的理解,不正确的一项是()。
(江苏2008C—10)2,6,15,28,(),78
计算机中“处理器”的基本功能是:从存储器中取出指令,按指令的要求对数据进行算术或逻辑运算,并把运算结果留在处理器中或送回存储器。下面是关于处理器的叙述: ① 处理器主要由运算器和控制器组成,它包含若干“寄存器”,用来临时存放数据 ② 大规模
Wheredotheguestspeakerscomefrom?
最新回复
(
0
)