Identify the components of the plasma membrane involved in facilitated diffusion

Facilitated diffusion, is a type of diffusion that uses a medium such as a channel in the plasma membrane for any particle to pass from high to low concentration gradient. Moreover, this type of transport is described as passive since it does not use ATP.  

answer: b: experiments that showed that all cells are similar in how they metabolize and in their composition

explanation:

answerparathyroid gland;