2. A normal adult male's small drop of blood contains approximately 5 million red blood cells.
3. An adult female's drop of blood contains about 500 thousand fewer cells than that of an adult male.
4. Did you know the average cell is about 8 thousandths of a millimeter in diameter?
5. The first cell is believed to have appeared 3.5 billion years ago.
6. A drop of blood is made up of 5 million red blood cells, and 10 thosand white blood cells.