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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.
Looking at the sun may not only cause headache and distort your vision temporarily, but it can also cause permanent eye damage. Any exposure to sunlight adds to the cumulative effects of ultraviolet (UV) radiation on your eyes. UV exposure has been linked to eye disorders such as macular degeneration, solar retinitis, and corneal dystrophies.
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.
In 1835 it was discovered that a disease of silkworms known as muscardine could be transferred from one silkworm to another, and was caused by a fungus.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.