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 m
Scientists have long believed one way to stop the Earth’ s atmosphere from warming is by planting more trees. The idea is that m
admin
2012-12-13
59
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 stone 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 tile 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.
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:https://kaotiyun.com/show/Lab7777K
0
大学英语六级
相关试题推荐
Thevastmajorityofpeopleinanygivenculturewill______totheestablishedstandardsofthatculture.
Henryremainedcalmand______unaffectedbytheterribleeventsofthepreviousday.
Theofficestaffarealmost______female.
Aforeignlanguageisa______courseinmiddleschoolsinChina.
Hisstatementisbeingseenas__________criticismoftheworkofresearchlaboratories.
ThepopulationinHongKongis______Chinese.
The______ofthescientificattitudeisthatthehumanmindcansucceedinunderstandingtheuniverse.
A、Nooneknows.B、TheChinesechefusedthewrongrecipes.C、Thehungryminersrequestedanewdishtobeserved.D、AChinesech
A、Theyshowfear.B、Theystarttocry.C、Theyturntoadults.D、Theyreachouttotouchthem.D短文提到,somebabies害怕陌生的成年人,但他们却会rea
随机试题
甲公司与乙公司签订一份技术开发合同,未约定技术秘密成果的归属。甲公司按约支付了研究开发经费和报酬后,乙公司交付了全部技术成果资料。后甲公司在未告知乙公司的情况下,以普通使用许可的方式许可丙公司使用该技术,乙公司在未告知甲公司的情况下,以独占使用许可的方式许
A.体重B.身长C.上、下部测量D.前囟E.上臂围体格测量可以反映一些生长发育及疾病情况,反映某些内分泌疾病有帮助的指标是
男,20岁,大学生。不食、不语伴行为异常6个月。曾在当地医院就诊,此次入院检查:神志清,仰卧,头颈悬空不动,无自发言语,拒绝服从医生的简单指令,眼球活动自如。有时候突然拍门或抢病友的东西。体格检查未见异常。能够最快缓解其症状的治疗措施是
哺乳期妇女用药注意事项包括
在下列微分方程中,以函数y=C1e-x+C2e4x(C1,C2为任意常数)为通解的微分方程是()。
出口口岸()征免()
对于二手个人住房贷款,商业银行最主要的合作单位是()。
负强化与惩罚在本质上是相同的。()
根据我国现行宪法的规定,有权制定基本法律的国家机关是()(2014年一综一第16题)
Itisoftenthroughgooddinnersthatonemakesfriends.InJapan,thereare【B1】______"DiningGroups"or"WineGroups",formedb
最新回复
(
0
)