Carbon dioxide makes up less than one percent of the Earth’s atmosphere, but the gas is very important to life on Earth. Scientists are finding that processes involving carbon dioxide affect our climate in ways that are difficult to understand. Last month, a committee of the National Academy...
A. oxygen (氧气) B. carbon dioxide (二氧化碳) C. nitrogen (氮气) D. hydrogen (氢气) 相关知识点: 试题来源: 解析 C 正确答案:C 解析:大气的主要成分是氮气(nitrogen)哦,大概占大气总成分的78%左右, 而氧气(oxygen)只占20%左右,剩余的2%由二氧化碳(carbon dioxide)等其他气体组成。反馈...
根据第一段中的“We all think plants were expected to get larger with increased carbon dioxide in the atmosphere, but changes in temperature, humidity(湿度)and nutrient availability seem to have trumped the benefits of increased carbon dioxide”可知科学家原来以为二氧化碳的增加会导致物种变大,但是气候...
We continue to add carbon dioxide to the atmosphere. 子句类型: 并列句 连接词: AND 3. 句子成分 子句-1 The burning of fossil fuels [主语] and [连接词] the clearing of forests [主语] have increased [谓语] atmospheric carbon dioxide [宾语] by about 15 percent in the last hundred year...
This results in a lot ofwaste, not only in the US, but also globally.Let's start at the beginning of the supply chain. Growing and harvesting beans requires energy which releases a lotof carbon dioxide (CO) into the atmosphere. Research found that one pound of roasted coffee produces an...
Firstly,paper bags and straws are made from trees.Trees,as you know,can reduce carbon dioxide levels in the atmosphere(大气).They can slow down climate change.An increase in the use of paper bags can cause more deforestation(毁林). Secondly,the production of paper things requ...
" The thin atmosphere on Mars is 96 percent carbon dioxide and much more(7) changeable( change) than on Earth and the temperature can vary by 100 degrees,"Hoffman said."One aim is to show we can run Moxie in all seasons." The device,Moxie,uses some special pumps,(8...
In 2010, the burning of fossil fuels and the production of cement (水泥) sent more than nine billion tons of carbon into the atmosphere, the new analysis found, with 57 percent of that coming from developing countries. On the surface, the figures of recent years suggest that wealthy ...
考生可能会根据文中的"there must have been higher concentrations of greenhouse gases in the atmosphere, most likely carbon dioxide"而误认为40亿年前,地球上含有浓度更高的诸如二氧化碳之类的温室气体,但是结合上文的"a then popular theory"和下文第三段中否定该理论的相关信息"There is no geologic(地质的)...
"Annex 1 countries" in the Kyoto Protocol-would need to cut carbon dioxide emissions 80 percent to 95 percent by 2050, compared with a base year of 1990, to maintain a concentration of greenhouse gases in the atmosphere of less than 450 parts per million (ppm) in carbon dioxide equivalent...