An allergy occurs when the immune system reacts abnormally to what type of substance?
AOnly to substances that are inherently toxic to everyone
BOnly to extreme temperatures
CTo substances that are typically harmless to most people
DOnly to bacteria and viruses
Explanation
An allergy occurs when a person’s immune system mistakenly identifies a normally harmless substance, such as pollen, certain foods, or pet dander, as a threat, triggering an unnecessary and sometimes uncomfortable or even dangerous immune response. Common allergy symptoms can range from mild, such as sneezing and itchy eyes, to severe, such as difficulty breathing in a serious allergic reaction called anaphylaxis. Because allergic responses vary significantly between individuals, a substance that causes a strong reaction in one person may have no noticeable effect on another. Explore more Everyday Science MCQs on mcqstutor to keep practicing.
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