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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?
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Did you know?
During the twentieth century, a variant of the metric system was used in Russia and France in which the base unit of mass was the tonne. Instead of kilograms, this system used millitonnes (mt).
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Eat fiber! A diet high in fiber can help lower cholesterol levels by as much as 10%.
Did you know?
Your heart beats over 36 million times a year.