So both of these two are two methods of gaining active immunity. One is via an artificial so immunization via a vaccine and the other one is a natural via the process of infection. Now, what about the temporary process of passive immunity which basically injects in one way or form antibodies into our body and those antibodies can bind onto the pathogenic antigens, labeling them for destruction. So we also have artificial and natural. Now, artificial includes actually taking those antibodies, injecting those antibodies into our body and allowing those antibodies to circulate our system. Now, the problem with this is it doesn't produce any memory cells.