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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.
Thyroid conditions may make getting pregnant impossible.
To combat osteoporosis, changes in lifestyle and diet are recommended. At-risk patients should include 1,200 to 1,500 mg of calcium daily either via dietary means or with supplements.
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).
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.