Question

What leads to long-term immunity in mammals? . . A. Exposure to an antigen . B. Action of an antibody . C. Barriers

Answer 1

A. Exposure to an antigen

Exposure to viruses and antigens led to the foundation of modern vaccination. Vaccination introduces an antigenic material that helps the ability of the immune system to adapt a specific pathogen, therefore leading to a long-term immunity.

Answer 2

Letter A. Exposure to an antigen leads to long-term immunity in mammals.