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Did you know?
The human body produces and destroys 15 million blood cells every second.
Did you know?
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Did you know?
The familiar sounds of your heart are made by the heart's valves as they open and close.
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?
Thyroid conditions may make getting pregnant impossible.