Define the following terms:
$(1)$ Diffusion
$(2)$ Facilitated Diffusion

(N/A) $(1)$ Diffusion: The movement of molecules of any substance from a region of higher concentration to a region of lower concentration is called diffusion. It is a passive and random process that does not require energy.
$(2)$ Facilitated Diffusion: When the movement of molecules across a membrane occurs from a region of higher concentration to a region of lower concentration with the help of special membrane proteins (carrier proteins) without the expenditure of energy,it is called facilitated diffusion.