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More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
Not getting enough sleep can greatly weaken the immune system. Lack of sleep makes you more likely to catch a cold, or more difficult to fight off an infection.
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.
There are more nerve cells in one human brain than there are stars in the Milky Way.