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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.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
There are more nerve cells in one human brain than there are stars in the Milky Way.
It is widely believed that giving a daily oral dose of aspirin to heart attack patients improves their chances of survival because the aspirin blocks the formation of new blood clots.
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.