Q: What system is responsible for defending your body against sickness?


Read this paragraph and choose the correct option from the provided answers:

Infectious diseases are diseases that spread from person to person. They are caused by pathogens such as bacteria, viruses or fungi. What can you do to avoid infectious diseases? Eating right and getting plenty of sleep are a good start. These habits will help keep your immune system healthy. With a healthy immune system, you will be able to fight off many pathogens. The next best way is to avoid pathogens. Though this is difficult, there are steps you can take to limit your exposure to pathogens.

 Choices:

- nervous system

- circulatory system

- digestion system

- immune system


A:
immune system