Three scientists — William G. Kaelin Jr. of the Dana-Farber Cancer Institute, Peter J. Ratcliffe of the University of Oxford, and Gregg L. Semenza of Johns Hopkins University — were awarded the 2019 Nobel Prize in Physiology or Medicine this morning for their research into one of the most important adaptive mechanisms for the survival of life. Through their separate contributions, the three scientists uncovered how cells sense and respond to the availability of oxygen, that key ingredient complex organisms need to move, build tissues and perform the diverse jobs that keep them alive.