<prompt> Which of the following viruses possesses DNA a capsid with icosahedral symmetry and no lipid envelopeHerpesvirusAdenovirusPoxvirusAll  <response>: Ans. is b Adenovirus Read the following facts and this question will seem very easy : . All nonenveloped viruses whether DNA or RNA have icosahedral symmetry. . Nonenveloped DNA viruses PAP - PApova, Adeno, PArvo . Nonenveloped RNA viruses -4 PCR - Picorna, Calci, Reo. Also know . All DNA viruses whether enveloped or nonenveloped have icosahedral symmetry except poxvirus which has complex symmetry. . No DNA virus has helical symmetry. . RNA viruses have either icosahedral or helical symmetry : Icosahedral symmetry -- Nonenveloped RAN viruses PCR -- Picorna, Calci, Reo and Retro, Flavi, Toga, Remember - RFT. Helical symmetry -- Rest of the RNA viruses. 