Your fingernails grow faster in summer.
744
Only humans shed emotional tears.
331
Every human spent about half an hour as a single cell.
144
Our brains have a negativity bias and will remember bad memories more than good ones.
15
Poor eyesight (myopia) is associated with higher IQ.
232
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11