In this form of transport, a molecule or ion that can fit in a transport channel is free to
move through the channel in either direction and diffuse toward the side of the cell
where it is least concentrated. this form of transport is called facilitated diffusion.
why?

The need activity of the nurse is to suction discharges from the trachea. current treatment approaches in the pressing consideration facilities or crisis offices are corticosteroids and nebulized epinephrine; steroids have demonstrated advantageous in extreme, direct, and even gentle croup. in the clear instances of croup, anti-microbials are not endorsed, as the etiology is viral

Distillation.  distillation is the correct answer.