Breathingis special in several respects: it is the only function you can perform consciously as well as unconsciously, and it can be a completelyvoluntaryact or a completelyinvoluntaryact, as it is controlled by two sets of nerves, one belonging to thevoluntarynervous system, the other to theinvoluntary. But Respiration isusually referredas a chemical reaction where Oxygen is used to breakdown Glucose in order to generate energy which is then used by the cell to function. This function can't be voluntary