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Did you know?
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
Did you know?
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Did you know?
The horizontal fraction bar was introduced by the Arabs.
Did you know?
Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Did you know?
The average human gut is home to perhaps 500 to 1,000 different species of bacteria.