Final answer:
Franklin used X-ray diffraction to reveal DNA's helical nature, while Watson and Crick, using her data among others', formulated the double helix model, earning them a Nobel Prize which did not include Franklin posthumously.
Step-by-step explanation:
Rosalind Franklin used X-ray diffraction methods to elucidate the helical nature of DNA, which was a pivotal discovery in understanding its structure. While Franklin provided the crucial X-ray diffraction data, it was James Watson and Francis Crick who built upon her findings and, together with additional information, such as Chargaff's rules, formulated the double stranded structural model of DNA, successfully modeling the molecule as a double helix. This groundbreaking work led to Watson, Crick, and Maurice Wilkins being awarded the Nobel Prize in Physiology or Medicine in 1962, although Franklin's contribution was significant, she had unfortunately passed away prior to the award and Nobel prizes are not awarded posthumously.