Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
When you get goosebumps and your hair stands, the hair helps to trap air, making you feel warmer by keeping in your body heat.
46
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
If your DNA was stretched out it would reach to the moon 6,000 times.
256
The human brain doesn't stop developing until about 25 years old.
102
Our Right Lungs takes more air than our left lung.
194