Respuesta :
Histamine. Your body produces this, which activates allergy symptoms. Please mark Brainliest!!!
Answer: Body's immune response.
Explanation:
When body encounters any foreign particles like pollen grain, fungi and some other allergens body evokes immune response.
The primary response of the body is generated by the immune system of the body. There is a increased mucus production and constricted airways so that more pollen grains cannot enter the body.