The question is how? Well, it turns out that one of the major agents, one of the major proteins in the complement system we call C Three, does not actually need something to activate itself so it can spontaneously break down into its active form to form the C three B and C three A. Now, the thing is, under normal conditions, when we don't have any pathogenic agents, for example, bacterial cells in our body, when we only have these normal cells around these molecules, what happens is the C three B quickly attaches onto a special inhibitory protein found on the membrane of nearby healthy cell. And that inhibitory protein inhibits and deactivates the C three B molecule. And then that molecule is essentially recycled to form something else, perhaps another C Three molecule. So under normal conditions, in the absence of any type of pathogens, this is usually what happens.