氧气,过去人们叫它“养气”,它维持着生命,并由生命产生.氧是地壳含量最多的物质,几乎占其总量的一半,占空气总质量的21%,占水总质量的89%,占树木总干重的42%. 氧气在大气的积累我们的银河系中,太阳系起源于50亿年前.45亿年前形成了地球.在绿色植物出现以前,原始大气并没有氧气,而是以Co_2、Co、甲烷和氨气为主的混合气体.绿色植 Oxygen, which people used to call it “nourishment,” is life-sustaining and life-forming. Oxygen is the substance with the most crustal content, accounting for almost half of its total, accounting for 21% of the total air mass and 89% of the total water mass %, Accounting for 42% of the total tree dry weight Oxygen accumulation in the atmosphere In our galaxy, the solar system originated 5 billion years ago and formed Earth 455 million years ago. Before the advent of green plants, the original atmosphere did not have oxygen, Co2, Co, methane and ammonia-based mixed gas