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Looking at the sun may not only cause headache and distort your vision temporarily, but it can also cause permanent eye damage. Any exposure to sunlight adds to the cumulative effects of ultraviolet (UV) radiation on your eyes. UV exposure has been linked to eye disorders such as macular degeneration, solar retinitis, and corneal dystrophies.
This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
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.
Nearly 31 million adults in America have a total cholesterol level that is more than 240 mg per dL.
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).