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Did you know?
The horizontal fraction bar was introduced by the Arabs.
Did you know?
Not getting enough sleep can greatly weaken the immune system. Lack of sleep makes you more likely to catch a cold, or more difficult to fight off an infection.
Did you know?
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
Did you know?
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
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.