A man's beard grows fastest when he anticipates sex.
239
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
The human brain uses approximately as much energy as a 10 watt light bulb.
120
The average person's skin weighs twice as much as their brain.
131
Yawns are more contagious among people with closer relationships.
163
On average, there's 100 billion neurons in the human brain.
83
