Yawns are more contagious among people with closer relationships.
163
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
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Every year your body replaces 98% of your atoms.
119
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99