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Did you know?
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.
Did you know?
Although puberty usually occurs in the early teenage years, the world's youngest parents were two Chinese children who had their first baby when they were 8 and 9 years of age.
Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.
Did you know?
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
Did you know?
About 100 new prescription or over-the-counter drugs come into the U.S. market every year.