Explanation: The secondary immune response provides long-lasting immunity because of the presence of memory B cells and memory T cells. These memory cells "remember" the specific antigen and can quickly mount a strong and effective immune response upon re-exposure to the same antigen, providing long-term protection.

Incorrect choices:

a. The primary immune response is primarily mediated by IgM antibodies, while the secondary immune response involves the predominance of IgG antibodies, which are more effective and provide long-lasting immunity.

b. The secondary immune response occurs after the primary immune response and is faster, not slower, due to the presence of memory cells.

c. Memory cells are a key component of the secondary immune response, playing a central role in providing rapid and robust immunity.

VI. Immune Disorders and Clinical Considerations: