The average sperm cell swims at 8 inches per hour.
4
For most people, no matter how hard you pinch the skin on your elbow with your fingers it doesn't hurt.
515
The human brain is more active during sleep than during the day.
28
If Earth's life was compressed into 1 year, then humans would have been around for only 2 seconds.
15
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Yawns are more contagious among people with closer relationships.
163
An average heart beats 100,000 times a day, pumping some 2,000 gallons of blood through its chambers. Over a 70-year life span, that adds up to more than 2.5 billion heartbeats.
73