When you kiss someone for the first time, you get a spike in the neurotransmitter dopamine, making you crave more.
23
Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
132
The adult human brain weighs about 3 pounds (1,300-1,400 g).
99
After age 30, the brain shrinks a quarter of a percent (0.25%) in mass each year.
139
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11
Every human spent about half an hour as a single cell.
144
Some monks can increase their body temperature so much they can dry soaking sheets in a freezing room!
31
Yawns are more contagious among people with closer relationships.
163