Yawns are more contagious among people with closer relationships.
163
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
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Every year your body replaces 98% of your atoms.
119
It takes twice as long to lose new muscle if you stop working out than it did to gain it.
127
The average sperm cell swims at 8 inches per hour.
76
Enamel is hardest substance in the human body.
61
If you are cold you are more likely to be hungry because you use energy to keep warm.
143