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This year, an estimated 1.4 million Americans will have a new or recurrent heart attack.
When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).
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.
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 modern decimal position system was the invention of the Hindus (around 800 AD), involving the placing of numerals to indicate their value (units, tens, hundreds, and so on).