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In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.
More than one-third of adult Americans are obese. Diseases that kill the largest number of people annually, such as heart disease, cancer, diabetes, stroke, and hypertension, can be attributed to diet.
In most cases, kidneys can recover from almost complete loss of function, such as in acute kidney (renal) failure.