Multiple choice Electrolytes are made up of chlorine and these two minerals sodium and potassium calcium and potassium sodium and phosphorus calcium and phosphorus Reveal answer Fill a bubble to check yourself A Correct answer Explanation The major electrolytes in the body's extracellular and intracellular fluids are sodium, potassium, and chloride (chlorine). Together, they maintain osmotic pressure, fluid balance, and proper nerve and muscle function.