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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).
There are more sensory neurons in the tongue than in any other part of the body.
There are 20 feet of blood vessels in each square inch of human skin.
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.
About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.