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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?
The ratio of hydrogen atoms to oxygen in water (H2O) is 2:1.
Did you know?
Asthma is the most common chronic childhood disease in the world. Most children who develop asthma have symptoms before they are 5 years old.
Did you know?
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Did you know?
After 5 years of being diagnosed with rheumatoid arthritis, one every three patients will no longer be able to work.