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About 600,000 particles of skin are shed every hour by each human. If you live to age 70 years, you have shed 105 pounds of dead skin.
Elderly adults are living longer, and causes of death are shifting. At the same time, autopsy rates are at or near their lowest in history.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
Vaccines prevent between 2.5 and 4 million deaths every year.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
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