Cracking your knuckles does not actually hurt your bones or cause arthritis. The sound you hear is just gas bubbles bursting.
18
Only 1% of bacteria cause disease.
45
The heart pumps about 1 million barrels of blood during an average lifetime!
30
Your heart will pump about 212 million liters in its lifetime.
26
In older people, memory is best early in the morning and then declines during the late afternoon.
33
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


