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Though the United States has largely rejected the metric system, it is used for currency, as in 100 pennies = 1 dollar. Previously, the British currency system was used, with measurements such as 12 pence to the shilling, and 20 shillings to the pound.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
The ratio of hydrogen atoms to oxygen in water (H2O) is 2:1.
On average, someone in the United States has a stroke about every 40 seconds. This is about 795,000 people per year.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.