It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
Stress can result in more headaches as a result of the body rerouting blood flow to other parts of the body.
92
Every human spent about half an hour as a single cell.
144
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
You forget 90% of your dreams.
256
When you kiss someone for the first time, you get a spike in the neurotransmitter dopamine, making you crave more.
23

