So these are the five quantities that we have to calculate every time we carry out one of these procedures. And then we also normally expose our extracted portion to SDS page to basically help us visualize if our technique is actually working. And if we combine these two methods, that gives us a very good idea if the purification technique is working. So normally, as we go from A to E, the number of bands should decrease. And what that means is we're getting rid of those unwanted proteins and we're focusing in on that protein that we actually want to study. And that is confirmed by these measurements because as we purify the sample, the specific activity has to increase and so should our purification level.