And what this basically means is whatever this substance is, when it enters this blood plasma, when it enters the glomerulus, it can easily pass across our glomerulus. And that means the concentration of this substance in the Bowman's capsule will be exactly the same as the concentration of the substance inside our blood plasma found in our glomerulus. Now not absorbed means when that substance is within our tubule of the nephron, it is not reabsorbed back into our peritubular capillaries. And not secrete means if any of this substance is found in the Ethernet arterial, it is not actually secreted by the peritubular capillaries back into our filter. So case number one freely filtered, not absorbed, not secret. So for a substance X that is freely filtered visaglomerilus, but it is neither reabsorbed nor secreted, what exactly will be our renal clearance.