You are presented with the question "Heavy metals are _." and the following answer choices: 
- emissions
 - dangerous
 - bent
 - homogenous
 - antigens
 - vehicles
 - fossil fuels
 - heat energy

Now knowing that antigens are molecules that the immune system recognizes as foreign to the body and heavy metals are, in general, foreign to the body, choose the best answer.


 

     antigens    