Final answer:
Antigens on the surface of pathogens allow the immune system to recognize and respond to specific pathogens.
Step-by-step explanation:
Antigens on the surface of pathogens are how the adaptive immune system recognizes specific pathogens. Antigen specificity allows for the generation of responses tailored to the specific pathogen. It is also how the adaptive immune system "remembers" the same pathogen in the future.