Answer:
Skin
The skin sheds excess salt through sweat
C6H12O6 (glucose) is the answer you are looking for
Natural selection occurs to give help the best survival chance to the organisms.
(1) they keep toxic substances out of the cell;
(2) they contain receptors and channels that allow specific molecules, such as ions, nutrients, wastes, and metabolic products, that mediate cellular and extracellular activities to pass between organelles and between the cell and the outside environment;
(3) they separate vital but incompatible metabolic processes conducted within organelles.