This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Which of the following viruses possesses DNA, a capsid with icosahedral symmetry and no lipid envelope -a) Herpesvirusb) Adenovirusc) Poxvirusd) Papovavirus \nSelect and explain. \nA. c, B. bd, C. ab, D. ac', 'role': 'user'}, {'content': 'Answer: B \nExplanation: All nonenveloped viruses (whether DNA or RNA) have icosahedral symmetry.\nNonenveloped DNA viruses → PAP - PApova, Adeno, PArvo\nNonenveloped RNA viruses —› PCR - Picorna, Calci, Reo.\n\nAlso know\n\nAll DNA viruses (whether enveloped or nonenveloped) have icosahedral symmetry except poxvirus which has complex symmetry.\nNo DNA virus has helical symmetry.\nRNA viruses have either icosahedral or helical symmetry :\nIcosahedral symmetry → Nonenveloped RAN viruses (PCR → Picorna, Calci, Reo) and Retro, Flavi, Toga, (Remember - RFT).\nHelical symmetry → Rest of the RNA viruses.', 'role': 'assistant'}]