In facilitated diffusion, what is the role of the transport proteins? A) The transport proteins allow solutes to move passively down their concentration gradient across the membrane.
B) The transport proteins provide a protein site for ATP hydrolysis, which facilitates the movement of a solute across a membrane.
C) The transport proteins provide energy for diffusion of the solute.
D) The transport proteins provide a low-resistance channel for water molecules to cross the membrane.

A

Explanation:

There is no much more to say than the letter A describes the process of facilitated diffusion.

The normal diffusion ocurres when the solute passes the membrane through the space of the double layer of phospholipids. Particles that are small and apolar can pass trough the membrane without problems.

For bigger or polar particles we need to use a protein system to help them pass into the cytoplasm. That's what we call Facilitated Difusion.

About the other options:

B) That's the explanation about active transport. That happen for every particle who is going against the gradient of concentration.

C) Again: if we are talking about diffusion, there is no energy needed.

D) The Water Molecules suffer the process os osmotic pressure. Water deslocates to the higher gradient of concentration - contraty what the other particles do.