Answer: High water content in the body.
Explanation:
Up to 60% of the human adult body is water. According to H.H. Mitchell
If the human body is mostly made up of water (H2O),The high percentage of oxygen can be accounted for since there is one atom of Oxygen in every molecule of water.
H2 + O. Oxygen with one atom in water has atomic mass of 16, which is greater than the atomic mass of Hydrogen with two atoms. Therefore because oxygen has a higher atomic size than hydrogen, Oxygen still contribute more to the human body mass.
