It takes about 20 seconds for a red blood cell to circle the whole body.
102
The largest cell in the human body is the female egg and the smallest is the male sperm.
682
Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Women have about four times as many foot problems as men; lifelong patterns of wearing high heels often are the culprit.
111
The human brain uses approximately as much energy as a 10 watt light bulb.
120
Dogs can be trained to identify the scent of lung cancer long before symptoms develop.
190
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
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