The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
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You forget 90% of your dreams.
256
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
82
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
Your thumb is about the same size as your nose.
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Obsessive nose picking is called Rhinotillexomania.
101
Every human spent about half an hour as a single cell.
144
When you kiss someone for the first time, you get a spike in the neurotransmitter dopamine, making you crave more.
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