Yawns are more contagious among people with closer relationships.
163
The human body contains over a billion miles of DNA.
147
If every muscle in your body could pull in one direction, you could lift nearly 25 tons.
22
The human brain doesn't stop developing until about 25 years old.
102
It takes about 20 seconds for a red blood cell to circle the whole body.
102
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
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
The largest cell in the human body is the female egg and the smallest is the male sperm.
682