<span>Observing that fibroblasts grew better in cell culture when blood serum was added to the growth medium instead of blood plasma. Thus proving that there was a substance in serum that made it easier for fibroblasts to grow.</span>
Platelets would help the blood clot, therefore preventing blood loss. White Blood Cells would help protect against infection. So, I believe the answer would be platelets & white blood cells.
Isaac Newton published a comprehensive theory of gravity in 1687. Though others had thought about it before him, Newton was the first to create a theory that applied to all objects, large and small, using mathematics that was ahead of its time.
