It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
A human brain produces as many as 12,000 to 50,000 thoughts per day, depending on how deep a thinker a person is.
23
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
Only humans shed emotional tears.
331
Early American humans hunted car-size armadillos and used their shells for houses.
12
You forget 90% of your dreams.
256
When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
You can't tickle yourself.
29