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The horizontal fraction bar was introduced by the Arabs.
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.
In the United States, an estimated 50 million unnecessary antibiotics are prescribed for viral respiratory infections.
Eating carrots will improve your eyesight. Carrots are high in vitamin A (retinol), which is essential for good vision. It can also be found in milk, cheese, egg yolks, and liver.
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.