Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The human brain doesn't stop developing until about 25 years old.
102
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Poor eyesight (myopia) is associated with higher IQ.
232
Your heart will pump about 212 million liters in its lifetime.
26
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515