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After 5 years of being diagnosed with rheumatoid arthritis, one every three patients will no longer be able to work.
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During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).
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The average adult has about 21 square feet of skin.
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Vaccines prevent between 2.5 and 4 million deaths every year.
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Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.