Add Yahoo as a preferred source to see more of our stories on Google. human red blood cells under microscope with two white blood cells When a pregnant woman had her blood sampled back in 1972, ...

Look at blood smeared across a slide under a microscope, and you see a mystery revealed. The ruby-colored, vital, fluid of life we call blood is made of lots of stuff. There is the liquid plasma that ...

Stem cells are precursors of a variety of different cells: They can turn into anything from blood to bone to muscle. Human blood stem cells, known as hematopoietic stem cells, are the forerunners of ...