Question: What is the function of memory cells in the immune system?

Options:

1. To produce immediate immune responses
2. To remember past infections and respond quickly upon re-exposure
3. To activate macrophages
4. To secrete cytokines

Correct Answer: To remember past infections and respond quickly upon re-exposure

Solution:

Memory cells are long-lived cells that remember past infections and enable a faster and more effective response upon re-exposure to the same pathogen.