Question

multiple - choice question
for water to travel across the cell membrane at a substantial rate, the water molecules travel through protein channels known as aquaporins. this is an example of which of the following?
active transport
facilitated diffusion
simple diffusion
rewatch

Explanation:

Facilitated diffusion uses protein channels to move substances across the cell - membrane down their concentration gradient. Water moving through aquaporins is an example of this as it doesn't require energy input and uses a channel protein. Active transport requires energy and moves substances against the concentration gradient. Simple diffusion is the movement of substances without the help of proteins.

Answer:

B. Facilitated diffusion