You are presented with the question "What can keep mold from entering the respiratory system?" and the following answer choices: 
- vaccinations
 - layers of fat
 - deep breaths
 - sweating
 - a breathing mask
 - moisture
 - organic molecules
 - hydrogen and oxygen

Now knowing that abreathing mask is used for keeping harmful particles from entering the respiratory system and when mold grows in the house, it can emit particles that travel through the air, choose the best answer.


 

     a breathing mask    