Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
21
The human eye blinks an average of 4,200,000 times a year.
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The average person's skin weighs twice as much as their brain.
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It takes approximately 12 hours for food to entirely digest.
93
You can't tickle yourself.
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Babies crawl an average of 200m a day.
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Enamel is hardest substance in the human body.
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We share 70% of our DNA with a slug.
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