During an action potential, depolarization occurs as a result of

K ions diffusing to the outside of the cell membrane
K ions diffusing to the inside of the cell membrane
Na ions diffusing to the outside of the cell membrane
Na ions diffusing to the inside of the cell membrane
Na and K ions not diffusing

Action potentials result from the depolarization of the cell membrane (the sarcolemma), which opens voltage-sensitive sodium channels; these become inactivated and the membrane is repolarized through the outward current of potassium ions.

its 'b'

Explanation:

materials water oxygen those are the things i can think of in this moment.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.