Which substances are needed for cellular respiration? use complete sentences to explain how the mass of hydrogen is conserved during cellular respiration.

Remember that the carbon cycle is, in fact, a cycle. Also keep in mind the law of conservation of mass. For cellular respiration to occur, you need energy. This energy is used and a waste product, usually carbon dioxide, is produced.
At point G, a factory is emitting carbon, which is then used in plants to produce glucose. This justifies this process by saying that carbon is beneficial to the environment.