By definition: Facilitated diffusion<span> is the process of spontaneous passive transport of molecules or ions across a cell's membrane via specific transmembrane integral proteins.~Google
An example, the only I can really think of:
Polar and large molecules normally can't cross the lipid bi layer using simple diffusion, it usually has to be </span>Facilitated diffusion
The correct answer is positive feedback.
Answer:
Cool dry air descends and heats up
