Answer and explanation:
Active and passive transport of solutes across a membrane differ essentially in the requirement of energy to impulse the process. Passive transport occurs in favor of the solute concentration gradient (from higher solute concentration to lower solute concentration) and it does not require energy supply. Ions and small hydrophobic molecules are commonly transported by passive transport across the plasmatic membrane. By other hand, active transport occur against the solute concentration gradient (from lower solute concentration to higher concentration) so it requires energy, usually supplied by ATP consumption. Membrane channels and pumps are often required in this kind of transport.