So our doctors basically can study the globeal filtration rate of our kidneys by giving the patient this substance and then study what our renal clearance is of our inulin. Now, let's move on to case number two. In case number two, we also have the substance freely filtered, but now it is fully reabsorbed and it is not secreted. So let's take a look at what that actually looks like. So we have 625 milliliters per minute coming in into our capillaries, the glomerulus. And because it is freely filtered, it passes freely across.