And this antibody is manufactured in a way to basically contain an enzyme. So we have an antibody shown in green, and that antibody is created so that it contains an enzyme attached to it. And we'll see why that's important in just a moment. That's why we call this method enzyme linked immunosorbin acid. Enzyme link means we create this monoclonal antibody shown in green that can bind specifically to this blue antibody. And that green antibody also contains an enzyme that will become important in step d. So in step c, an enzyme linked antibody that can bind to that antibody of interest, the blue one, is added to our mixture, to our well.