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The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
Your skin wrinkles if you stay in the bathtub a long time because the outermost layer of skin (which consists of dead keratin) swells when it absorbs water. It is tightly attached to the skin below it, so it compensates for the increased area by wrinkling. This happens to the hands and feet because they have the thickest layer of dead keratin cells.
Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.
In ancient Rome, many of the richer people in the population had lead-induced gout. The reason for this is unclear. Lead poisoning has also been linked to madness.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.