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.
21
Your thumb is about the same size as your nose.
124
The lense of the eye continues to grow throughout a person's life.
34
You would need to smoke between 20,000-40,000 joints to be at risk of dying of a THC overdose.
12
Chocolate, sex, and laughter are all important for a healthy brain.
37
The human brain is insensitive to pain.
76
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18