Answer:
It allows the body to keep pathogen information for future infections.
Step-by-step explanation:
Vaccination is the process whereby a substance called VACCINE is injected into body in order to prepare the immune system for resistance against infections. A vaccine contains the harmless or dead version of a pathogen called ANTIGEN, which functions to give the immune system defense mechanism against that form of pathogen in future.
The vaccine works by stimulating the immune system of the body to fight against the antigens in the same way it will fight against an actual pathogen in the future. Hence, the body keeps the information on how to combat such pathogens when there is an actual infection.