This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Biochemistry
[{'content': 'primary structure of amino acid is mainly detected by ? \nSelect and explain. \nA. mass spectroscopy, B. xray crystallography, C. nmr spectrometry, D. all the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: primary structure - detected by = mass spectroscopy (edmans techinique) secondary structure /teiary structure = xray crystallography /nmr spectrometry ref : vasudevan 9th ed', 'role': 'assistant'}]