Yawns are more contagious among people with closer relationships.
163
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
The average sperm cell swims at 8 inches per hour.
76
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
The human brain doesn't stop developing until about 25 years old.
102
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Your thumb is about the same size as your nose.
124