Now, this is in its inactive form. But to be activated, what must happen is the constant region of the antibody that is bound to its complementary antigen has to bind onto this C One Q complex of C One. So basically, to be more specific, we have five different types of antibodies in our body. We have five different types of immunoglobulins. And two of these immunoglobulins that are capable of binding to this C One complex are immunoglobulin M and immunoglobulin G. So let's suppose immunoglobulin M. This antibody finds its complement antigen, it binds to it, and then that complex goes on and binds onto the C One Q portion of the C One protein. And then that activates C one R, and then that activates C one S. Now, C one X is actually C one S is actually a serene protease.