Question

the image shows facilitated diffusion. how is it different from simple diffusion?
facilitated requires a protein channel
no difference, just another term for the same thing
facilitated goes against the gradient; simple goes with the gradient

Explanation:

Simple diffusion is the movement of molecules from an area of high - concentration to low - concentration without the help of a transport protein. Facilitated diffusion also moves molecules down their concentration gradient but requires a protein channel or carrier protein to assist the movement of larger or polar molecules across the cell membrane.

Answer:

facilitated requires a protein channel