Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
Your heart will pump about 212 million liters in its lifetime.
26
Chewing gum boosts your brain power.
285
Your thumb is about the same size as your nose.
124
Yawns are more contagious among people with closer relationships.
163
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
The largest cell in the human body is the female egg and the smallest is the male sperm.
682