A substance is present in concentration of 2 mg% in the afferent aeriole and zero mg% in the efferent. TRUE about the substance is:

Presence of ceain substance in the afferent aeriole and its absence in the efferent aeriole indicates that all of it has freely filtered in glomerulus. Most of the useful organic nutrients in the plasma that should not be lost in the urine are freely filtered. These include glucose, amino acids, acetate, Krebs cycle intermediates, some water-soluble vitamins, lactate, acetoacetate, beta-hydroxybutyrate, and many others. Ref: Eaton D.C., Pooler J.P. (2013). Chapter 5. Renal Handling of Organic Solutes. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 8e.