Enamel is hardest substance in the human body.
61
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
It has been scientifically proven that stroking a cat can lower one's blood pressure!
456
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
The human brain doesn't stop developing until about 25 years old.
102
It takes about 20 seconds for a red blood cell to circle the whole body.
102
The human brain is more active during sleep than during the day.
28