Allergy to pollen is classified as:
an autoimmune reaction
immunodeficiency
delayed hypersensitivity
immediate hypersensitivity

The correct answer is D. Immediate hypersensitivity

Explanation:

Allergies are different conditions that occur when an organism is exposed to an allergen, which is a substance, elements, etc that leads to an abnormal immune response. Because of this, allergies are mainly explained as immediate hypersensitivity in the immune system as they usually occurred shortly after the organisms are exposed to the allergen and it is a. Types of allergies include allergies to food, allergic asthma, etc that lead to symptoms such as sneezing, swelling rashes, etc. Therefore, allergy to pollen as any other allergy is classified as an immediate hypersensibility.

c is the correct answer hope this !

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds