These are probably the four most common cases that you should be familiar with. Case number one. So we basically have freely filtered through the glomerulus. 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.