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In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
Adolescents often feel clumsy during puberty because during this time of development, their hands and feet grow faster than their arms and legs do. The body is therefore out of proportion. One out of five adolescents actually experiences growing pains during this period.
Since 1988, the CDC has reported a 99% reduction in bacterial meningitis caused by Haemophilus influenzae, due to the introduction of the vaccine against it.
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.
The immune system needs 9.5 hours of sleep in total darkness to recharge completely.