Yawns are more contagious among people with closer relationships.
163
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
The human brain doesn't stop developing until about 25 years old.
102
The human brain uses approximately as much energy as a 10 watt light bulb.
120
There are about 255 babies born worldwide every minute.
46
By weight, Bone is five times stronger than steel.
417
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11