Modern humans first appeared about 200,000 years ago, but record keeping didn't begin until about 6,000 years ago. That means about 97% of human history is lost.
21
Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
132
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
A human brain produces as many as 12,000 to 50,000 thoughts per day, depending on how deep a thinker a person is.
23
Unconsciousness will occur after 8-10 seconds after loss of blood supply to the brain.
93
Coughing can cause air to move through your windpipe faster than the speed of sound - over a thousand feet per second!
197
On average, there's 100 billion neurons in the human brain.
83
It took 200,000 years for humans to reach 3 billion in number. It took 40 years for the next 3 billion.
11