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    Why do people yawn?

    +1  Views: 400 Answers: 3 Posted: 14 years ago

    3 Answers

    Although scientists still cannot pinpoint the exact biological mechanisms of a yawn, they agree that it is an involuntary reflex that controls the oxygen and carbon dioxide levels in the blood.
    Because they're too tired or too bored...like me right now (yawwn :O)
    Yawning cools the brain and increases blood flow. Thus making it efficient.


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