Adaptive immunity is primarily characterized by its ability to recognize and remember specific __________, enabling a more effective response upon reinfection.

Adaptive immunity is primarily characterized by its ability to recognize and remember specific antigens, allowing the immune system to mount a faster and stronger response when the same pathogen appears again. When a T cell or B cell first encounters an antigen, it binds to that exact molecular shape and begins to multiply. Some of these cells become memory cells that stay in the body for years. Then, if the same antigen enters again, the memory cells quickly activate, producing a rapid and powerful attack. For example, after a first chickenpox infection, memory cells remember the varicella virus’s surface proteins and eliminate it swiftly if you are exposed again.