Dr Margolin realised that something was wrong when he noticed that his wallet was missing from his shirt pocket and he was not sure how and where he had lost his wallet. He also couldn’t understand that his true love, Raizel, being present at the wedding, looked too young, and he was in a dilemma that she might be her daughter, who was trying to mock him. All these events led Dr Margolin to a confused state of mind.
Study the given molecular structure of double-stranded polynucleotide chain of DNA and answer the questions that follow. 
(a) How many phosphodiester bonds are present in the given double-stranded polynucleotide chain?
(b) How many base pairs are there in each helical turn of double helix structure of DNA? Also write the distance between a base pair in a helix.
(c) In addition to H-bonds, what confers additional stability to the helical structure of DNA?