The key answer of exercise 1

Allergies occur when the immune system reacts to a substance that is usually harmless. The immune system mistakenly identifies this substance, known as an allergen, as a threat and produces an immune response. Common allergens include:

• Pollen: Pollen from trees, grasses, and weeds can trigger seasonal allergies (hay fever or allergic rhinitis).
• Dust mites: Microscopic organisms that thrive in indoor environments, especially in bedding, upholstery, and carpets.
• Pet dander: Tiny, airborne particles of skin, fur, or feathers shed by pets like cats, dogs, birds, and rodents.
• Mold spores: Mold can grow in damp environments, and its spores can become airborne, triggering allergic reactions.
• Insect venom: Stings or bites from bees, wasps, hornets, fire ants, and other insects can cause allergic reactions in some people.
• Certain foods: Common food allergens include peanuts, tree nuts, milk, eggs, soy, wheat, fish, and shellfish.
• Medications: Some individuals may be allergic to certain medications, such as antibiotics (e.g., penicillin), nonsteroidal anti-inflammatory drugs (NSAIDs), or certain types of anesthesia.
• Latex: Latex, found in rubber gloves, balloons, and some medical devices, can cause allergic reactions in some people.
• Certain plants: Contact with certain plants, such as poison ivy, oak, or sumac, can cause allergic skin reactions.
• Airborne irritants: Certain pollutants or irritants in the air, including tobacco smoke, pollution, and strong odors, can trigger allergic reactions or worsen existing allergies.

It's important to note that each individual's immune system reacts differently, and what causes an allergic reaction in one person may not affect another. Allergies can range from mild to severe, and some allergic reactions can be life-threatening (anaphylaxis). If you suspect you have allergies, it's advisable to consult with a healthcare professional for proper diagnosis and management.