The familiar sounds of your heart are made by the heart's valves as they open and close.
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The average adult has about 21 square feet of skin.
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Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
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Vaccines prevent between 2.5 and 4 million deaths every year.
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Critical care patients are twice as likely to receive the wrong medication. Of these errors, 20% are life-threatening, and 42% require additional life-sustaining treatments.
Anterior and lateral views of the body illustrating directional terms.