Question

4
When is the adaptive immune system active

А All the time
B Only when there's a repeat infection
C Only after pathogens start to multiply
D Only when a person acquires autoimmunity

Answer 1

Explanation:

Adaptive immunity is an immunity that occurs after exposure to an antigen either from a pathogen or a vaccination. This part of the immune system is activated when the innate immune response is insufficient to control an infection.