So the antigen antibody or the antibody antigen complex goes on and activates all these inactivated proteins found in our bloodstream, as we'll see in just a moment. And then those activated proteins go on and create a cascade of events, many different processes that eventually label those antigens for destruction and kill off those pathogenic agents that created those antigens in the first place. So to see exactly what we mean by that, let's discuss some of these proteins that are part of the classical pathway that are part of the complement system. And let's begin with the first protein known as complement One, or simply C One. Now, C One is actually a protein complex that consists of three different protein subunits. We have C one Q, we have C one S and C one R. And to be more specific, we have six molecules of C one Q here shown in blue.