Active immunity results when an immune response to a pathogen produces memory cells, and pathogens are germs that cause disease. Given these facts, active immunity is when an immune response occurs after a germ produces what among the following options:
- harmful substances
 - bioaerosols
 - rapid expansion
 - Allergies
 - anemia
 - it needs them
 - Chemical energy
 - memory cells


 

        memory cells 