Which element below is considered the most versatile element in living organisms and why?
a) hydrogen, because it is a key component in organic molecules and provides most of the mass of human bodies
b) hydrogen, because it can be found in both organic and inorganic molecules
c) carbon, because it can bond with many elements to form complex molecules
d) carbon, because it provides strength to the important protein, keratin

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.