Viruses do not possess a cellular machinery. They consist of a nucleic acid (DNA & RNA) core surrounded by a protein sheath and are considered to be an organism.
(2) The bodies of certain fungi are made up of protoplasm and nuclei.
(3) RBCs and sieve tube cells continue to live without nucleus and other vital organelles.
(4) Bacteria and blue-green algae do not have an organised nucleus. Their genetic material (DNA) is naked and the cell organelles are absent