If the concentration of phosphate in the cytosol is 2.0 mm and the concentration of phosphate in the surrounding fluid is 0.1 mm, how could the cell increase the concentration of phosphate in the cytosol?

a) passive transport
b) diffusion
c) active transport
d) osmosis
e) facilitated diffusion

The correct option is C. The concentration of phosphate inside the cytosol is already greater than the concentration of phosphate in the surrounding fluid, yet, the cell still want to move more phosphate into the cell. To do this, energy is needed to move the phosphate ions against the concentration gradient, so the type of transportation requires is ACTIVE TRANSPORT.