Answer 1 of 5. The cellular respiration is a complex biological process that breaks down sugars fat and proteins and transforms these materials into energy for the functioning of the organism. The Reason They Tell You On Planes To Put The Oxygen Mask On Yourself First Is Because If You Don T Have Oxygen You W Helping Others Oxygen Mask Care About You This process is called respiration. Why is oxygen necessary . Carbon dioxide is a waste product of that process. - Get the answer to this question and access a. Why is oxygen important to human life. Quality Oxygen Concentrator - Adjustable Continuous Oxygen Flow Shop Now ship from USA. Every day about seven hundred billion cells in our bodies wear out and must be replaced. Having the right oxygen levels in the body is essential as lots of body functions depend on this aspect. At lower PO2 levels your red blood cells make more of a substance called 23-diphosphoglycerate. It is important to note that while the brain co...