Yawns are more contagious among people with closer relationships.
163
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
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
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
It takes about 20 seconds for a red blood cell to circle the whole body.
102
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22