Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Enamel is hardest substance in the human body.
61
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
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
Most of us have microscopic, worm like mites named Demodex that live in our eyelashes and have claws and a mouth.
-137
Poor eyesight (myopia) is associated with higher IQ.
232
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118