Watson and Crick model is for
High-Yield Explanation
Watson and crick model Double helical structure of DNA.Adjacent bases are seperated by 0.34nm. The diameter or width of the helix is 2 nanometers. Phosphate bonds form the rail of stair case. Bases jutting inside form the steps of staircase. REF :DM VASUDEVAN TEXTBOOK;8th EDITION ;Page no 557.