Explain why living organisms contain more hydrogen atoms than any other atoms, yet 65% of a typical organism’s mass is oxygen.

The reason is that Oxygen atoms contain 16 times more mass than Hydrogen atoms.

Hydrogen H11 Has only one proton and no neutrons and so has an atomic number of 1 and a mass of 1

Oxygen O168 Has 8 protons and also 8 neutrons and having atomic number of 8 and a mass of 16.

Hydrogen takes 16 Hydrogen atoms to equal the mass of 1 oxygen atom.

stress fractures occur largely in the feet and legs and are common in sports that require repetitive impact, primarily running/jumping sports such as gymnastics or track and field.