Answer:
Active transport requires energy in order to move molecules against the concentration gradient while simple and facilitated diffusion require no energy to move molecules down the concentration gradient.
Explanation:
Active transport requires energy as the substance move from low concentration to high concentration (substances move against concentration gradient).
For example, Sodium-potassium pump.
Passive transport does not require energy as the substance move from high concentration to low concentration (substances move only down their concentration gradient).
It is of two types: Simple and facilitated transport.
For example, Osmosis.
