This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Which of the following requires a carrier protein? 
Select and explain. 
A. Exocytosis, B. Facilitated diffusion, C. Simple diffusion, D. Osmosis
B: Facilitated diffusion
Answer: B: Facilitated diffusion 
Explanation: Facilitated diffusion is the process of spontaneous passive transpo of molecules or ions across a cell&;s membrane specific transmembrane integral proteins.