Final answer:
A) Memory is the correct answer as it refers to the capacity of the immune system to quickly mobilize antigen-specific lymphocytes upon subsequent exposures to a previously encountered pathogen.
Step-by-step explanation:
The correct answer to the question is Memory. Memory is an important characteristic of specific immunity because it allows for the rapid and more effective mobilization of lymphocytes that are specific to an antigen upon subsequent exposures. This immunological memory is a hallmark of adaptive immunity, distinguishing it from the innate immune response. For instance, after recovering from an infection such as chickenpox, the body's immune system retains a memory of the varicella-zoster virus, enabling it to prompt a fast and tailored response if re-exposure occurs. As a result, symptoms are often milder or even non-existent during re-infection due to this adaptively acquired immunity.