It takes about 20 seconds for a red blood cell to circle the whole body.
102
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
When you kiss someone for the first time, you get a spike in the neurotransmitter dopamine, making you crave more.
23
Poor eyesight (myopia) is associated with higher IQ.
232
The human eye blinks an average of 4,200,000 times a year.
233
Playing Tetris after a traumatic event can prevent the development of traumatic memories and reduce the chance of having flashbacks.
29
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11