Yawns are more contagious among people with closer relationships.
163
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
After age 30, the brain begins to lose about 50,000 neurons per day - shrinking the brain .25% each year.
55
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
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
Enamel is hardest substance in the human body.
61
If your DNA was stretched out it would reach to the moon 6,000 times.
256
Every year your body replaces 98% of your atoms.
119