How does the concentration gradient affect the rate of simple diffusion compared to facilitated diffusion?

• A. Simple diffusion rate increases linearly with concentration gradient, while facilitated diffusion rate increases rapidly but eventually plateaus.
• B. Both simple and facilitated diffusion rates increase linearly with concentration gradient.
• C. Facilitated diffusion rate decreases as concentration gradient increases.
• D. Simple diffusion rate decreases as concentration gradient increases.

Answer: (A)