<prompt> What are the major functions of I cells?Reabsorb potassium ion.Secrete potassium ion.Excrete potassium ion.All of the above  <response>: Reabsorb potassium ion.REABSORPTION IN LATE DISTAL TUBULE:Functionally similar to coical collecting tubule.Facultative type:Reabsorption of soluteswater depends on waterelectrolyte balance.Hence, Facultative type of absorption.Cells involved in reabsopion:Principal P cells.Intercalated I cells.FUNCTIONS OF I CELLS:Reabsorb potassium ion.Secrete hydrogen ions into tubular lumen. 