You are presented with the quiz "What can be caused by direct or passive inhalation?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "lung cancer is most often caused by exposure to tobacco smoke" and "smoke Tobacco smoke , whether directly or passively inhaled, has been shown to worsen asthma". 

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


 

     lung cancer      