X-ray diffraction data collected by Rosalind Franklin and Maurice Wilkins helped Watson and Crick solve the structure of DNA. Which aspect structure of DNA did the data help them solve?
A. the double-stranded nature of the helix and its dimensions
B. the ratio of bases
C. the presence of deoxirybose sugars
D. The presence of hydrogen bonds between bases

Rosalind Franklin and Maurice Wilkins used a method of X-ray crystallography to investigate the structure of the DNA. It was a diffraction method and the scattering pattern of the X-ray was recorded on a film and used to elucidate details of molecular structure of the DNA. From the scattering pattern produced by the DNA molecule, they could infer the double helical nature of the DNA molecule and the arrangement of phosphates. They took the x-ray diffraction photograph of DNA known as the “photograph 51” depicting the double helix. By using this data about the double helical nature of the DNA, James Watson and Francis Crick proposed the structure of DNA in 1953.