Enamel is hardest substance in the human body.
61
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
The human brain uses approximately as much energy as a 10 watt light bulb.
120
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Gorillas can catch human colds and other illnesses.
205
The human brain is more active during sleep than during the day.
28
The average sperm cell swims at 8 inches per hour.
4
In one day, adult lungs move about 10,000 litres of air.
11