The prime driving force for counter current multiplier system is
Ans. (b) Reabsorption of Na+ in thick ascending limb(Ref: Ganongy 25th ed/p.685)The primary driving force for counter current system is Reabsorption of Na+ in thick ascending limb through Na-K-2Cl cotransporter
Medullary hyperosmolarity
Reabsorption of Na+ in thick ascending limb
Action of ADH via aquaporin channels
Urea recycling
Kidneys and Body Fluids