A student researching allergies has taken notes:
• Allergies occur when the immune system overreacts to harmless substances • Common triggers include pollen, dust mites, and certain foods • Symptoms range from mild sneezing to life-threatening anaphylaxis • Allergies have increased significantly in developed countries • The hygiene hypothesis suggests cleaner environments may be a factor
The student wants to explain what causes allergic reactions.
Common allergy triggers include pollen, dust mites, and certain foods.
Allergies occur when the immune system mistakenly identifies harmless substances as threats and overreacts, producing symptoms from sneezing to severe anaphylaxis.
Allergy rates have increased significantly in developed countries.
The hygiene hypothesis suggests overly clean environments may contribute to allergies.
Correct Answer: B
Choice B. Immune overreaction to harmless substances explains the cause.