Problem: Eddie and Agnes are a couple who have been married for 40 years and have very different approaches to their health. Agnes gets a check-up every year during the fall that includes a flu shot. Eddie hates going to the doctor and keeps telling Agnes that he feels fine and "if it ain t broke, don t fix it" . Eddie gets very sick with the flu in March and Agnes is fine and is able to take care of her husband who struggles just to lift his head from the pillow. After Eddie gets better, he wants to know why he got so sick, while Agnes didn't. How would you explain this to Eddie? What are memory cells? What is a secondary response and who had a secondary response?