Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases

Viruses : (a) They are non-cellular organisms.
(b) They remain inert outside living cell. They have genetic material DNA or RNA. No virus has both RNA and DNA.
© Plant infecting viruses have ssRNA but animal infecting viruses possess dsRNA.
Viruses causes diseases like (1) mumps, (2) small pox, (3) herpes and (4) influenza.