Background: An allergy is a disease in which the immune system makes an inflammatory response to a harmless antigen . Any antigen that causes an allergy is called an allergen. Allergens may be inhaled or ingested, or they may come into contact with the skin. Two common causes of allergies are shown in Figure below . Inhaling ragweed pollen may cause coughing and sneezing. Skin contact with oils in poison ivy may cause an itchy rash. Other common causes of allergies include dust mites, mold, animal dander, insect stings, latex, and certain food and medications. Symptoms of a common allergy such as pollen can include sneezing, a runny nose, nasal congestion and itchy, watery eyes.

Situation: Two roommates, Karen and Kelly, have decided to adopt a pet for their apartment. They are debating between getting a dog or a cat when they decide to flip a coin since they can't agree. The coin comes up tails so they are getting a cat. Unbeknownst to Karen, she is allergic to cats. Kelly has no allergies to animals, but Karen has never lived with cats before so she isn't aware that she is allergic to them.

Question: Who will have a stuffy nose more often?
Answer: Karen

Situation: Two roommates, Karen and Kelly, have decided to adopt a pet for their apartment. They are debating between getting a dog or a cat when they decide to flip a coin since they can't agree. The coin comes up tails so they are getting a cat. Unbeknownst to Karen, she is allergic to cats. Kelly has no allergies to animals, but Karen has never lived with cats before so she isn't aware that she is allergic to them.

Question: Who will have a stuffy nose less often?
Answer: Kelly

Situation: Two roommates, Karen and Kelly, have decided to adopt a pet for their apartment. They are debating between getting a dog or a cat when they decide to flip a coin since they can't agree. The coin comes up tails so they are getting a cat. Unbeknownst to Karen, she is allergic to cats. Kelly has no allergies to animals, but Karen has never lived with cats before so she isn't aware that she is allergic to them.

Question: Will Kelly's eyes be more or less itchy than Karen's eyes?
Answer: less

Situation: Two roommates, Karen and Kelly, have decided to adopt a pet for their apartment. They are debating between getting a dog or a cat when they decide to flip a coin since they can't agree. The coin comes up tails so they are getting a cat. Unbeknownst to Karen, she is allergic to cats. Kelly has no allergies to animals, but Karen has never lived with cats before so she isn't aware that she is allergic to them.

Question: Will Karen's eyes be more or less itchy than Kelly's eyes?
Answer: more

Situation: Two roommates, Karen and Kelly, have decided to adopt a pet for their apartment. They are debating between getting a dog or a cat when they decide to flip a coin since they can't agree. The coin comes up tails so they are getting a cat. Unbeknownst to Karen, she is allergic to cats. Kelly has no allergies to animals, but Karen has never lived with cats before so she isn't aware that she is allergic to them.

Question: Who will struggle the most when holding the cat?
Answer: Karen

Situation: Two roommates, Karen and Kelly, have decided to adopt a pet for their apartment. They are debating between getting a dog or a cat when they decide to flip a coin since they can't agree. The coin comes up tails so they are getting a cat. Unbeknownst to Karen, she is allergic to cats. Kelly has no allergies to animals, but Karen has never lived with cats before so she isn't aware that she is allergic to them.

Question: Who will struggle the least when holding the cat?
Answer: Kelly