And what that means is our body develops these memory cells. And these memory cells contain a copy of the antibody that is specific to that antigen that infected our body in the first place. And what that is useful for. If we are ever reinfected by that same pathogen that contains that same antigen, we have these memory b cells that can now initiate a very quick and a very rapid response. And we actually won't feel the same exact effect that we felt the first time when we were infected by that pathogen. So the process of active immunity is a process in which our body develops immunity, these memory cells to the pathogen by being directly exposed to our antigens.