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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.
Vaccines prevent between 2.5 and 4 million deaths every year.
According to research, pregnant women tend to eat more if carrying a baby boy. Male fetuses may secrete a chemical that stimulates their mothers to step up her energy intake.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
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