So if we look at this box in region, instead of having a drop in the PH, we have a very, very gradual move. And so instead of adding a small amount to change our PH drastically, we have to add a lot of the acid to actually create the same drastic change in PH. So this relatively flat curve basically means so the flat curve means that our system is able to actually resist and prevent drastic changes in PH from actually taking place. So once again, by adding acid to a buffered solution to a water solution that contains a buffered system, there is a much more gradual change of PH as seen in this box region. The question is, why does the PH change gradually? Well, because of what we said earlier.