Which feature distinguishes facilitated diffusion from active transport?

1. A Option A: Facilitated diffusion moves substances down a concentration gradient without using ATP
2. B Option B: Facilitated diffusion needs no membrane proteins
3. C Option C: Facilitated diffusion only moves water
4. D Option D: Facilitated diffusion uses ATP to move substances against a gradient

Answer checked 11 October 2026 · How we write and check questions