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Author Question: A 5.0-kg mass sits on the floor of an elevator that has a downward acceleration of 1.0 m/s2. On top ... (Read 3631 times) |
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.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
Elderly adults are living longer, and causes of death are shifting. At the same time, autopsy rates are at or near their lowest in history.
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).
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.