Fact 1: Immunodeficiency occurs when the immune system is not working properly.

Fact 2: Malnutrition , particularly with lack of protein , can cause acquired immunodeficiency.

Given the two facts above, answer the question "What can cause the immune system to not work properly?" with the following options: 
- cigarettes
 - Malnutrition
 - burning coal
 - Healthy food
 - Exercise
 - Good health
 - Allergies
 - Pesticides


 

  Malnutrition       