<span>They are made up of nitrogen bases, sugars, and phosphates.
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An atom is unlikely to react when it is stable. That is when it's shell is complete. Due to the completion of the shell, no other electron can combine through any form of bonding. Hope i helped.
Discovery of structure of DNA by Franklin and Watson and Crick.
Explanation:
Rosalind Franklin was researching about DNA structure at the King’s College at London based on x-ray diffraction studies; while, Crick and Watson were researching on the same at the Cambridge University based on Linus Pauling discovery of proteins.
Once when Watson happen to listen to Franklin’s lecture upon DNA structure and how it depends on relative humidity of the air and other facts relating to DNA; he along with Crick made physical DNA models which became a big failure.
Later, Franklin found that a wet form of DNA with high humidity had a helix like structure. This point became the base of later discovery of Watson and Crick’s double helix model of DNA along with the discovery of DNA molecules being made up of double chain of nucleotides.