Fact 1: Abreathing mask is used for keeping harmful particles from entering the respiratory system.

Fact 2: Allergies are a reaction of the immune system to harmful particles in the air.

Given the two facts above, answer the question "What can prevent an allergic reaction?" with the following options: 
- chemical messengers
 - prolactin release
 - with their fur
 - sweating
 - Breathing mask
 - deoxyribonucleic acid
 - Cooking
 - hormones


 

     Breathing mask    