TF/P ratio for PCT for many substances are shown in diagram below. Which of them represents urea?

Ans. B. 2Line 1: Not reabsorbed or actively secreted in PCT e.g. PAH, Creatinine, Inulin.Line 2: Freely filtered and poorly reabsorbed like UreaLine 3: no change in concentration along PCTLine 4: Bicarbonate: 90% is reabsorbed in PCT decreasing its tubular fluid concentration Line5: Solute fully reabsorbed in PCT like glucose.