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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).
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Blood in the urine can be a sign of a kidney stone, glomerulonephritis, or other kidney problems.
More than 150,000 Americans killed by cardiovascular disease are younger than the age of 65 years.
Parkinson's disease is both chronic and progressive. This means that it persists over a long period of time and that its symptoms grow worse over time.