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
When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
A man's beard grows fastest when he anticipates sex.
239
A human being loses an average of 40 to 100 strands of hair a day.
133
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
It takes about 20 seconds for a red blood cell to circle the whole body.
102
Your fingernails grow faster in summer.
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