Which of the following organisms are acellular?

Viruses are acellular organisms - they consist only of genetic material (DNA or RNA) enclosed in a protein coat (capsid), lacking cellular organelles, cytoplasm, or cell membranes. They cannot reproduce independently and require a host cell. In contrast, bacteria are single-celled prokaryotes, fungi are multicellular or unicellular eukaryotes with chitin cell walls, and algae range from unicellular to multicellular eukaryotes.