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Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
There are 20 feet of blood vessels in each square inch of human 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.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Everyone has one nostril that is larger than the other.
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