Yawns are more contagious among people with closer relationships.
163
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
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