The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
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The modern decimal position system was the invention of the Hindus (around 800 AD), involving the placing of numerals to indicate their value (units, tens, hundreds, and so on).
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Though the United States has largely rejected the metric system, it is used for currency, as in 100 pennies = 1 dollar. Previously, the British currency system was used, with measurements such as 12 pence to the shilling, and 20 shillings to the pound.
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Individuals are never “cured” of addictions. Instead, they learn how to manage their disease to lead healthy, balanced lives.
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Vaccines prevent between 2.5 and 4 million deaths every year.