What is the mutation caused by the addition of a nucleotide to an already existing gene sequence called? a. deletion b. duplication c. insertion d. inversion

American scientist, linus pauling, was one of many scientists racing to discover the molecular structure of dna. pauling initially thought that the molecule was a triple helix. later, james watson and francis crick unveiled their double helix model, which turned out to be an accurate description of the molecule's shape. why did watson and crick succeed when pauling failed?