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Did you know?
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.
Did you know?
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Did you know?
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).
Did you know?
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.
Did you know?
Vaccines prevent between 2.5 and 4 million deaths every year.