<prompt> Site of maximum bicarbonate absorption-Proximal convoluted tubuleDistal convoluted tubuleCortical collecting ductMedullary collecting duct  <response>: Ans. is a i.e., Proximal convoluted tubule o About 80-90 of filtered HCO3- is absorbed in PCT.o Absorption of HCO3- is indirect, which is due to secretion H, i.e., secretion of H is coupled with absorption of HCO3o Filtered HCO3- reacts with H to form H2CO3 which then is dissociated into H2O and CO2.o CO2 diffuses into epithelial cell and generate HCO3- which is then reabsorbed. 