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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.
The familiar sounds of your heart are made by the heart's valves as they open and close.
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
The effects of organophosphate poisoning are referred to by using the abbreviations “SLUD” or “SLUDGE,” It stands for: salivation, lacrimation, urination, defecation, GI upset, and emesis.
More than nineteen million Americans carry the factor V gene that causes blood clots, pulmonary embolism, and heart disease.