Select the statement below that describes a critical finding of the Franklin DNA diffraction experiment. Group of answer choices That the phosphate groups are stabilized by the presence of divalent metals in solution That base stacking is the primary force holding the DNA helix together That B-form DNA helices have a pitch of approximately 34 angstroms That the DNA bases are predominantly found in their keto form That the number of adenine residues is always equal to the number of thymine residues in a double stranded DNA molecule

That B-form DNA helices have a pitch of approximately 34 angstroms

Explanation:

Rosalind Franklin was an X-ray crystallographer whose work contributed to the discovery of the molecular structure of DNA molecule by Watson and Crick. B-form DNA is the most common form of DNA, which consists of a right-handed double helix. B-form DNA was discovered by Watson and Crick based on the X-ray diffraction image of DNA (popularly known as image 51) obtained by Franklin. The pitch refers to the distance after every 10 base pairs along the DNA helix for one complete double-helix turn. This distance in the B-DNA helix is 34 Ångströms (i.e., 3.4 nanometers).