Answer:
a. The concentration gradient drives the movement
Explanation:
In passive transport such as osmosis or simple diffusion, there is no expenditure of ATP thanks to the concentration gradient, there is movement of water and solutes. The movement by gradients usually occurs from an area of greater concentration to another of lower concentration until equilibrium is achieved until the concentrations are matched to the side and side of the membrane. This movement is given by the lipid part of the membrane or through membrane proteins.
