Final answer:
An allergic response can be triggered by pollen, dust mites, pet dander, and other common allergens such as mold, specific foods, insect stings, and certain medications.
Step-by-step explanation:
An allergic response can be triggered by pollen, dust mites, pet dander, and other common allergens such as mold, specific foods, insect stings, and certain medications. These substances, known as allergens, can be inhaled, ingested, or come into contact with the skin or eyes, leading to various symptoms depending on the type and severity of the immune system response.