Enamel is hardest substance in the human body.
61
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
There are times when you're walking that the pressure on your feet exceeds your body weight, and when you're running, it can be three or four times your weight.
62
The human brain doesn't stop developing until about 25 years old.
102
Your heart will pump about 212 million liters in its lifetime.
26
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190