Given the question: Answer the following question given this paragraph: Your body's first line of defense is like a castle's moat and walls. It keeps most pathogens out of your body. The first line of defense includes physical, chemical, and biological barriers. Q: What is the purpose of your body's first line of defense? Choices: - reject foreign bodies - fight or flight - heal wounds - to keep out pathogens A:
The answer is:
to keep out pathogens