Final answer:
During a secondary adaptive response, there are many more Memory B cells compared to the Naïve B cells at the start of a primary adaptive response.
Step-by-step explanation:
The question is asking about the comparison between the number of Memory B cells and Naïve B cells at the start of a secondary adaptive response and the beginning of a primary adaptive response.
During a primary immune response, when a pathogen is encountered for the first time, plasma cells and T cells increase, but ultimately reach a plateau. At the same time, a subset of the naïve B and T cells differentiate into memory cells with the same antigen specificities. On reexposure to the same pathogen, memory B cells differentiate into plasma cells immediately, resulting in a more rapid production of immune defenses compared to the primary response.
Therefore, there will be many more Memory B cells at the start of a secondary adaptive response than there were Naïve B cells at the beginning of a primary adaptive response.