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Without (Oxygen) as a final electron acceptor, much energy would not be captured. The processes using ( ) release over 90% of the available energy in food. Other respiratory processes result in the oxidation (loss of electrons and hydrogens) from the atoms of ( ) to form carbon dioxide. Carbon dioxide, when it reacts with water, forms (CO2) which lowers the pH of the solution. In summary, our bodies need oxygen to release all of the energy from food and the bodies also need to eliminate carbon dioxide to maintain the blood pH homeostasis.