Final answer:
True, the driving force for simple diffusion is the movement of molecules down their electrochemical gradient, which occurs without the need for energy as substances move from areas of higher to lower concentration.
Step-by-step explanation:
The statement that the driving force for simple diffusion is moving down its electrochemical gradient is true. Simple diffusion is a naturally occurring process where a substance moves from an area of higher concentration to one of lower concentration, effectively down its concentration gradient.
This process does not require any energy input and relies on the random motion of particles, which can include gasses like O₂ and CO₂, or any substance that is soluble and can permeate the cellular membrane without assistance.