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The horizontal fraction bar was introduced by the Arabs.
Drying your hands with a paper towel will reduce the bacterial count on your hands by 45–60%.
Essential fatty acids have been shown to be effective against ulcers, asthma, dental cavities, and skin disorders such as acne.
When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).
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.