(a) b Fig(a unenveloped/helical (tobacco mosaic virus):(b)unenveloped/icosahedral (adenovirus);(c)enveloped/helical (paramyxovirus):(d)enveloped/icosahedral (herpesvirus).Fig. (a) unenveloped/helical (tobacco mosaic virus): (b) unenveloped/icosahedral (adenovirus); (c) enveloped/helical (paramyxovirus): (d) enveloped/ icosahedral (herpesvirus)