Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
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
A human brain produces as many as 12,000 to 50,000 thoughts per day, depending on how deep a thinker a person is.
23
You can't tickle yourself.
29
Yawns are more contagious among people with closer relationships.
163
Having sex can make a woman look younger and more attractive due to the release of estrogen and collagen.
346
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
One human hair can support 3 ounces.
191