(D)Cells rely on external energy to move molecules.
Explanation;
Active transport is the movement of dissolved molecules into or out of a cell through the cell membrane, from a region of lower concentration to a region of higher concentration using energy in the form of ATP.
In this type of transport,particles move against the concentration gradient, using energy released by hydrolysis of ATP.
Examples of active transport includes; uptake of glucose in the small intestines and uptake of ions from the soil by root hair cells in plants.
