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Approximately 15–25% of recognized pregnancies end in miscarriage. However, many miscarriages often occur before a woman even knows she is pregnant.
Vaccines prevent between 2.5 and 4 million deaths every year.
The familiar sounds of your heart are made by the heart's valves as they open and close.
Bacteria have been found alive in a lake buried one half mile under ice in Antarctica.
The average adult has about 21 square feet of skin.
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