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问：人类吸入氧气,呼出二氧化碳；植物正好相反,白天能够吸收二氧化碳,释放氧气,那么,多少棵树能提供一个人存活的充足氧气? 答：科学家告诉我们,一个普通人每年需要的氧气数量是13万升。在日照情况下,树木利用光合作用,吸收二氧化碳,释放氧气,但是夜晚,却和人类一样,释放二氧化碳,消耗氧气。相对来说,树木释放的氧气要比消耗的氧气多。但是不同的环境,树木释放的氧气数量也不同。在热带雨林,扣除树消耗的氧气外,热带雨林每棵树每年释放氧气的平均值达到27．3万升。但在干燥的沙漠里,刺柏
Q: Humans inhale oxygen and exhale carbon dioxide. In contrast, plants can absorb carbon dioxide and release oxygen during the day. How many trees can provide enough oxygen for a person to survive? A: Scientists tell us that the amount of oxygen an ordinary person needs every year is 130,000 liters. In the sunshine, trees use photosynthesis to absorb carbon dioxide and release oxygen, but at night, like humans, they release carbon dioxide and consume oxygen. In contrast, trees release more oxygen than they consume. But in different environments, the amount of oxygen released by the trees is also different. In the tropical rain forest, the average value of oxygen released by each tree in the rain forest reaches 273,000 liters, excluding the oxygen consumed by the trees. But in the dry desert, juniper