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There are 20 feet of blood vessels in each square inch of human skin.
There are more bacteria in your mouth than there are people in the world.
The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
The familiar sounds of your heart are made by the heart's valves as they open and close.
Malaria was not eliminated in the United States until 1951. The term eliminated means that no new cases arise in a country for 3 years.
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