Some of the carbon therefore ends up as soot, rather than carbondioxide, and oxygen that should be combining with carbon combines with nitrogen from the air instead.
Plants form themselves literally out of thin air, combiningcarbondioxide, water and the energy of sunlight to give themselves substance.
严格来讲，植物通过空气中的二氧化碳、水分以及太阳光来为自身提供养分。
3
Inside a fire, oxygen molecules break bigger molecules apart into carbondioxide and water vapor. All the heat and light of a fire comes from big, carbon-based molecules combining with oxygen.