Which scientist determined that the fundamental unit of DNA was a nucleotide containing one of four possible bases, a sugar molecule, and a phosphate group

The scientist who determined that the fundamental unit of DNA was a nucleotide containing one of four possible bases, a sugar molecule, and a phosphate group is Phoebus Levene. He is an American biochemist who focused on the study of the structure and the function of nucleic acids. He is responsible for characterizing different forms of nucleic acid, DNA and RNA.