Final answer:
The DNA double helix structure was discovered by Watson and Crick with the help of X-ray crystallography data provided by Rosalind Franklin. Their joint efforts led to the iconic model of DNA, though Franklin's crucial contributions were only widely acknowledged later, as she had passed away before the Nobel Prize was awarded.
Step-by-step explanation:
The structure of the DNA double helix was deduced by Watson and Crick using various experimental data, including that of X-ray crystallography by Rosalind Franklin. In the 1950s, Francis Crick and James Watson worked collaboratively at the University of Cambridge, England, to determine DNA's structure. At King's College London, Franklin used X-ray diffraction methods to analyze the structure of DNA. Her data were critical in aiding Watson and Crick in formulating the double-stranded helical model for DNA. Unfortunately, Franklin's contribution was not recognized with a Nobel Prize, as the award is not given posthumously and she had passed away by the time it was awarded to Watson, Crick, and Wilkins in 1962.