Answer:
The correct answer is: Immunity.
Step-by-step explanation:
The process of introducing weakened microbes into the body is called vaccinating and it is key to protect not only the individual getting the vaccine, but also the whole population through a phenomenon called "herd immunity".
For every antigen (a molecule that triggers an immune response) there is a specific antibody designed to fight it. Vaccines contain a weakened version of a specific antigen, so that when it enters the body is encounters the proper antibodies to fight it. This way, vaccines train the immune system to prepare for the possible encounter of this pathogen.