Mars had an oxygen-rich atmosphere around 4 billion years ago
13
Your body is creating and killing about 2.4 million red blood cells per second.
17
There is a mass reservoir of water floating in space that is 100,000 times bigger than our sun and holds 140 trillion times more water than all of our oceans.
11
Pet dogs and elephants are the only animals that seem to instinctively understand human gesture.
14
An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
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