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

Fact 2: Iron deficiency causes anemia and it weakens the immune system.

Given the two facts above, answer the question "What can low iron cause?" with the following options: 
- contamination
 - Pollution
 - decrease stamina
 - harmful substances
 - immunodeficiency
 - the ground shaking
 - cloudy and rainy weather
 - Temperature changing


 

     immunodeficiency    