- Glucose (C6H12O6): a six-carbon sugar molecule derived from carbohydrates like glucose and stored energy.

- Oxygen (O2): obtained from the air we breathe.

Respiration is a process that occurs in the mitochondria of cells. It involves the breakdown of glucose in the presence of oxygen to produce energy in the form of ATP (adenosine triphosphate), carbon dioxide (CO2), and water (H2O).