首页
登录
职称英语
Scientists have long believed one way to stop the Earth’s atmosphere from wa
Scientists have long believed one way to stop the Earth’s atmosphere from wa
游客
2023-11-22
65
管理
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. [br] What happened to the leaves falling from the trees in the second study?
选项
A、They broke down and the main parts turned into oxygen.
B、They broke down and the carbon content had mainly turned into carbon dioxide.
C、They broke down and the carbon content was mainly absorbed in the soil.
D、They absorbed more carbon dioxide.
答案
B
解析
关键语句: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.而A,C,D均错误。
转载请注明原文地址:http://tihaiku.com/zcyy/3209214.html
相关试题推荐
Doesbrainpower______aswegetolder?Scientistsnowhavesomesurprisingansw
ItiscommonlybelievedintheUnitedStatesthatschooliswherepeoplego
ItiscommonlybelievedintheUnitedStatesthatschooliswherepeoplego
ItiscommonlybelievedintheUnitedStatesthatschooliswherepeoplego
Whatconclusioncanbedrawnfromthescientists’observation?[br][originalte
TheChineseof3,500yearsagobelievedthattheearthwasachariot,andt
TheChineseof3,500yearsagobelievedthattheearthwasachariot,andt
TheChineseof3,500yearsagobelievedthattheearthwasachariot,andt
Toprovetheirtheories,scientistsmust______anadequateamountofdataasev
Youngscientistscannotrealize______soonthatexistingscientificknowledgeis
随机试题
Bettybroketheschoolrulesandregulationsrepeatedlysotheprincipalfinally
Overahundredyearsago,CharlesDickensshockedmanyofhisreaderswhenh
中小学研究性学习的目标。
Revit中族分类为以下几种?()A.可载入族 B.嵌套族 C.系统族 D
A.酯类局麻药 B.酰胺类局麻药 C.两者均有 D.两者均无变态反应(
关于城市设计的表述中,正确的是( )。A.城市总体规划编制中应当运用城市设计的
简述现代企业人力资源管理各个历史发展阶段的特点。
基础心理学是研究()。 (A)正常成人心理现象的心理学基础学科 (B
晚期肝硬化最常见的死亡原因是A.上消化道出血 B.感染 C.肝性脑病 D.
A.国际老年学会规定65岁以后 B.是指妇女从接近绝经时出现与绝经有关的临床特
最新回复
(
0
)