To reabsorb essential nutrients, electrolytes, and water
To secrete hydrogen ions and ammonia into the filtrate
To absorb HCO₃⁻ from the filtrate
All of the above
Solution
PCT plays a crucial role in urine formation by reabsorbing nearly all of the essential nutrients, and 70-80 per cent of electrolytes and water. It also helps to maintain the pH and ionic balance of the body fluids by selective secretion of hydrogen ions and ammonia into the filtrate and by absorption of HCO₃⁻ from it.