You are presented with the question "Breathing masks are used to keep harmful particles from entering the mouth and the what?" and the following answer choices: 
- body
 - eyes
 - air
 - skin
 - gullet
 - nose
 - ears
 - lungs

Now knowing that abreathing mask is used for keeping harmful particles from entering the respiratory system and oxygen enters the respiratory system through the mouth and the nose, choose the best answer.


 

      nose   