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The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Russia has the highest death rate from cardiovascular disease followed by the Ukraine, Romania, Hungary, and Poland.
About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Normal urine is sterile. It contains fluids, salts, and waste products. It is free of bacteria, viruses, and fungi.
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