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If all the neurons in the human body were lined up, they would stretch more than 600 miles.
Sperm cells are so tiny that 400 to 500 million (400,000,000–500,000,000) of them fit onto 1 tsp.
There are 60,000 miles of blood vessels in every adult human.
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.
About 60% of newborn infants in the United States are jaundiced; that is, they look yellow. Kernicterus is a form of brain damage caused by excessive jaundice. When babies begin to be affected by excessive jaundice and begin to have brain damage, they become excessively lethargic.