The average sperm cell swims at 8 inches per hour.
76
There are about 1,400 different species of bacteria in your belly button.
10
The human brain doesn't stop developing until about 25 years old.
102
All humans have the ability to see ultraviolet light, but it is passively filtered out by the eye's lens. People who undergo surgery to remove the lens can detect ultraviolet light.
22
You can hear the blood flowing through your ears if you find a quiet place and cover them tightly.
17
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22