And these are used not only to regulate the PH, but they are also used to actually control the zmodic pressure inside our blood. Number five, we also find waste products. So when the cells carry out their processes, they produce waste products such as, for example, urea, lactic acid, and our carbon dioxide. And these things are released into our blood and they end up in their specific location. For example, lactic acid ends up in the liver, our carbon dioxide ends up inside our lungs, and urea ends up in our kidneys. Now, what about number six?