Fact 1: Active immunity results when an immune response to a pathogen produces memory cells.

Fact 2: Pathogens are germs that cause disease.

Given the two facts above, answer the question "Active immunity is when an immune response occurs after a germ produces what?" with the following options: 
- harmful substances
 - bioaerosols
 - rapid expansion
 - Allergies
 - anemia
 - it needs them
 - Chemical energy
 - memory cells


 

        memory cells 