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
All of the following transpo processes follow 'saturation kinetics' except 
Select and explain. 
A. Facilitated diffusion, B. Na+ - Ca2+ exchanger, C. Simple diffusion, D. Na+ coupled active transpo
C: Simple diffusion
Answer: C: Simple diffusion 
Explanation: Diffusion primarily depends on the concentration of molecules. Passage of ions or molecule from a region of higher concentration to a lower concentration without the expenditure of energy is called diffusion. (REF TEXTBOOK OF MEDICAL PHYSIOLOGY GEETHA N 2 EDITION, PAGE NO - 4)