Question

A vaccine puts into the body weakened/dead pathogenic material, which by itself is incapable of causing disease. How does this help to protect the body in the case of infection by a live pathogen?

Answer 1

It helps the immune system recognize the pathogen and be more aware about the pathogen for a certain period of time. Therefore if a LIVING version of that pathogen were to enter the immune system, the immune system would be able to react to the pathogen quicker.

Answer 2

D. A vaccine causes the secretion of antibodies which remain in blood and fight the pathogen at the time of an infection.