Enamel is hardest substance in the human body.
61
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
The human brain doesn't stop developing until about 25 years old.
102
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
If you are cold you are more likely to be hungry because you use energy to keep warm.
143
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
The average person's skin weighs twice as much as their brain.
131