The human brain is more active during sleep than during the day.
28
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
You can't tickle yourself.
29
A human being loses an average of 40 to 100 strands of hair a day.
133
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
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