The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
Having sex can make a woman look younger and more attractive due to the release of estrogen and collagen.
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It takes about 20 seconds for a red blood cell to circle the whole body.
102
Babies crawl an average of 200m a day.
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The human brain uses approximately as much energy as a 10 watt light bulb.
120
It takes approximately 12 hours for food to entirely digest.
93
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
Tigers can see 6 times better at night than humans.
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