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The horizontal fraction bar was introduced by the Arabs.
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.
Illness; diuretics; laxative abuse; hot weather; exercise; sweating; caffeine; alcoholic beverages; starvation diets; inadequate carbohydrate consumption; and diets high in protein, salt, or fiber can cause people to become dehydrated.
Nitroglycerin is used to alleviate various heart-related conditions, and it is also the chief component of dynamite (but mixed in a solid clay base to stabilize it).
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).