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

Because Oxygen atom is heavier in mass than hydrogen atom.

Explanation:

High amount of hydrogen is present in the body in the form of water. In water, two hydrogen atoms and one oxygen atom are present. About 65 % of body mass is covered by oxygen atom, while hydrogen covers 10 % of body mass, it is because oxygen atom is 16 times heavier in mass than hydrogen atom. Mass number of hydrogen is 1 amu while mass number of oxygen atoms is 16 amu.

within 30 of the equator hope this