Answer:
echolocation
it sends waves for them to see around them.
Explanation:
 
        
                    
             
        
        
        
The correct answer is B(c?): <span>chlorofluorocarbons. Their reaction with ozone molecules is catalysed by UV radiation, oxygen (O2) is a product. Ozone is an important component of the atmosphere because it protects Earth's surface from UV. </span> 
        
             
        
        
        
During the initial exposure to the allergen, contact is made with B cells, these B cells differentiate and produce IgE antibody. The IgE antibodies which works against the allergens are released into the blood stream where they binds to Fc receptors which are located on mast cells and basophils. Now, the mast cells has become sensitized and they will wait patiently for the second exposure. When contact with the allergen is made the second time, the allergen becomes attached to the IgE present on the mast cells and this result in degranulation which trigger a lot of allergic responses.