The question above is intended to assess your ability to write two letters, one answering the other. For that reason, I can't write the letters for you, but I'll show you how to write them.
First, you must understand that letters establish communication between doctor and patient and for that reason, these letters need to be written in a formal and cultured language.
Based on this, to write these letters, you must:
Research a type of illness and look at symptoms and ways of treating it.
Begin the first letter, with the individual showing the symptoms he or she is experiencing and desiring an indication from the physician of what he or she should do to prevent those symptoms from prevailing.
Show how this individual is concerned about the symptoms and wants to get rid of them.
Start the second letter by showing the doctor's answer.
In this answer, the doctor presents the cause of the symptoms, shows how to treat, and asks the patient to go to the office, to receive better guidance.
