So d. Now we continue our process, we continue pouring and we increase the amount of volume and we might change our PH. And then once we see that a second amino acid loops, then we write down how much volume we use and what the PH of that buffer was. We compare it to our textbook value and we see that it is this quantity here. So the x axis basically describes the volume of the buffer that is added in order to loot that amino acid. So in this area, we have a very acidic buffer that we use. In this area, it's not as acidic.