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There are more nerve cells in one human brain than there are stars in the Milky Way.
Approximately 500,000 babies are born each year in the United States to teenage mothers.
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
In 2012, nearly 24 milliion Americans, aged 12 and older, had abused an illicit drug, according to the National Institute on Drug Abuse (NIDA).
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