You are presented with the question "A breathing mask can prevent what kind of particle from entering the lung?" and the following answer choices: 
- light
 - harmful
 - rabies
 - A virus
 - x-ray
 - deadly
 - ion
 - small

Now knowing that abreathing mask is used for keeping harmful particles from entering the respiratory system and unlike larger particles, the smaller particles are able to enter the respiratory system, choose the best answer.


 

        small 