Teacher:Given a scientific passage and an answer, generate a question for the given answer.
Teacher: Now, understand the problem? Solve this instance: Passage: Your immune system usually protects you from pathogens and keeps you well. However, like any other body system, the immune system itself can develop problems. Sometimes it responds to harmless foreign substances as though they were pathogens. Sometimes it attacks the body's own cells. Certain diseases can also attack and damage the immune system and interfere with its ability to defend the body. Answer: immune system
Student:
What protects you from pathogens and keeps you healthy?