It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
Men are more attracted to women whose bone structure is similar to their own mothers. It's called "sexual imprinting".
18
The higher the income, the more likely an American man will cheat on his wife.
94
In a lifetime, an average person walks the equivalent of 5 equators
177
If Earth's life was compressed into 1 year, then humans would have been around for only 2 seconds.
15
One million Americans, about 3,000 each day, take up smoking each year. Most of them are children.
-86
Yawns are more contagious among people with closer relationships.
163
