Although allergic reactions are triggered by allergens like pollen and fungi, the actual cause of the symptoms like mucous production and constricted airways is a) the body's immune response. b) the effect of medical treatment. c) the surrounding weather conditions. d) the clogging effect of the allergens.

A) the body's immune response.

Explanation:

Pollen and fungi are natural allergens which may get administered in the body  as a foreign antigen. In response to these foreign antigens the body generates an immune response by producing antibodies. These antibodies fight against antigens so that they cannot harm the body in any way. Therefore, symptoms of fever, production of mucous and constricted airways are the examples of production of antibodies in order to generate immune response.  

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave