For instance, we know that the physiological PH of our body, for example, of our blood, is around 7.4. And what that means is most of the biological systems in our body have to remain as this PH. Now, to resist PH change, our body uses these same buffer systems that we just described. And we have various types of acids that are in place depending on what the PH is that we want to essentially stick around to. For example, one acid that is used by our body is phosphoric acid. So we have this acid, and this is the conjugate base.