Which of the following always changes from one atom of an element to another atom of a different element?? A- number of electrons
B- charge
C- Number of hydrogens
D- number of outer shell electrons
E- number of protons

Number of protons

Explanation:

A is false because an atom can have a varying number of electrons and still be the same element, just a different isotope of the element

B is false because the charge of the atom only comes into play when two or more atoms are interacting

C is false bc... well. Hydrogen is literally an element.

D is false because the number of outer shell electrons (valence electrons) just determines what group (or column) the element is in on the periodic table

your answer would be a, maximum exploitation of resources.