You are presented with the question "What can low iron cause?" and the following answer choices: 
- contamination
 - Pollution
 - decrease stamina
 - harmful substances
 - immunodeficiency
 - the ground shaking
 - cloudy and rainy weather
 - Temperature changing

Now knowing that immunodeficiency occurs when the immune system is not working properly and iron deficiency causes anemia and it weakens the immune system, choose the best answer.


 

     immunodeficiency    