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Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
Blood is approximately twice as thick as water because of the cells and other components found in it.
Though the United States has largely rejected the metric system, it is used for currency, as in 100 pennies = 1 dollar. Previously, the British currency system was used, with measurements such as 12 pence to the shilling, and 20 shillings to the pound.
The highest suicide rate in the United States is among people ages 65 years and older. Almost 15% of people in this age group commit suicide every year.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.