You are presented with the quiz "What has a negative impact on the lungs?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "amold spore has a negative impact on the respiratory system" and "major components of the respiratory system are the lungs, trachea, nose, and the cell". 

So, what's the best answer to the question?


 

   mold spore        