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Plant Gas Scientists have been studying natural sources of methane (甲烷，沼气) for decades but hadn’t regarded plants as a producer, notes Frank Keppler, a geochemist(地球化学家) at the Max Planek Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment. Previously, researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes(微生物) need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as me A. Methane becomes less poisonous. B. Methane is turned into a fertilizer. C. Less methane reaches the atmosphere. D. Air becomes cleaner. [单项选择]以下疾病引起的呼吸衰竭属于泵衰竭的是（）。
A. 重症支气管哮喘 B. 肺栓塞 C. 急性间质性肺炎 D. 吉兰-巴雷综合征 E. ARD [单选题]压缩空气
A.压缩空气 B.人力 C.摩擦力 D.杠杆传动比 [多项选择]以企业价值或股东财富或企业股价最大化作为财务管理目标，其优点包括（）。
A. 考虑了资金的时间价值和投资的风险价值 B. 反映了对企业资产保值增值的要求 C. 有利于保持公司股价稳定 D. 有利于克服经营管理上的片面性和短期化行为 E. 有利于社会资源的合理配置，有利于实现社会效益最大化 [单选题](44175)一长三短声是()。
A.预报信号 B.警报信号 C.确报信号 D.停车信号 [判断题]露天场所，天气不良危及人身安全时也可上高处作业。
A.正确 B.错误 [判断题]按结构的不同，变电站终端分为壁挂式和柜式两种。
A.正确 B.错误 [简答题]People were being poisoned by__________
[多选题]以下属于浅孔爆破的是（ ）。
A. L=3m B. L=4m C. L=6m D. L=10m E. L=13m [单选题]在电路中,电源产生的功率( )负载消耗功率与内阻损耗的功率之和。
A.大于 B.小于 C.等于 [判断题]入口收费数据车辆车牌准确率应达到98%,车型准型确率应达到98%。( )
A.正确 B.错误 我来回答: 提交
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