What type of molecules can pass through the cell membrane by facilitated diffusion? 

Facilitated diffusion is a type of passive transport that allows certain molecules to cross the cell membrane with the help of specific transport proteins. The transport proteins act as channels or carriers that allow molecules to move down their concentration gradient without requiring energy. The types of molecules that can pass through the cell membrane by facilitated diffusion are those that are too large, too polar, or too charged to pass through the lipid bilayer by simple diffusion. 
Charged molecules, such as ions, and large molecules, such as glucose and amino acids, can pass through the cell membrane by facilitated diffusion through specific channels or carriers.