Yawns are more contagious among people with closer relationships.
163
A human being loses an average of 40 to 100 strands of hair a day.
133
The human brain is more active during sleep than during the day.
28
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
The average person's skin weighs twice as much as their brain.
131