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About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.
The familiar sounds of your heart are made by the heart's valves as they open and close.
There are 60,000 miles of blood vessels in every adult human.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Women are 50% to 75% more likely than men to experience an adverse drug reaction.
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