Yawns are more contagious among people with closer relationships.
163
The human brain is very soft, having a consistency similar to soft gelatin or firm tofu.
13
Enamel is hardest substance in the human body.
61
Your heart will pump about 212 million liters in its lifetime.
26
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
The average sperm cell swims at 8 inches per hour.
76
It would take about 1,200,000 mosquitoes to fully drain the average human body of blood.
217
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18