This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
[{'content': 'Watson and Crick model is for \nSelect and explain. \nA. DNA, B. mRNA, C. rRNA, D. tRNA', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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.', 'role': 'assistant'}]