You are presented with the question "What organ is harmed by air pollution?" and the following answer choices: 
- piano
 - church organ
 - heart
 - harp
 - bushes
 - animals
 - eardrum
 - lungs

Now knowing that air pollution harms the respiratory and circulatory systems and sulfur dioxide can irritate the respiratory system and damage the heart and circulatory system, choose the best answer.


 

   heart      