Respuesta :
I think the correct answer from the choices listed above is option B. External stimulus is the type of stimulus an allergen, such as pollen, is classified. This is because this allergen is obtained outside the body. So it must be external. Hope this answers the question. Have a nice day.
Answer:
B. external stimulus
Explanation:
Response to stimulus happens when we touch a hot object and immediately move our hand.
Pollen is an external stimulus. When pollen enters our air passage we sneeze immediately.
An internal stimulus is an acid reflux when we have digestion disorder.
A inborn stimulus is our immune system, as a result we are able to fight infections.