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Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
The National Institutes of Health have supported research into acupuncture. This has shown that acupuncture significantly reduced pain associated with osteoarthritis of the knee, when used as a complement to conventional therapies.
The top five reasons that children stay home from school are as follows: colds, stomach flu (gastroenteritis), ear infection (otitis media), pink eye (conjunctivitis), and sore throat.
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.