Enamel is hardest substance in the human body.
61
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
Yawns are more contagious among people with closer relationships.
163
Your heart will pump about 212 million liters in its lifetime.
26
It takes about 20 seconds for a red blood cell to circle the whole body.
102
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
Your body is creating and killing about 2.4 million red blood cells per second.
17