The best response for comparing a virus to a unicellular organism is:
Unicellular organisms have a cell membrane made from a lipid bilayer; viruses have a protein coat.
This statement accurately highlights a key structural difference between viruses and unicellular organisms. Viruses are not considered living organisms in the traditional sense because they lack cellular structures and cannot carry out metabolic processes or reproduce independently, while unicellular organisms are indeed living and can carry out life processes on their own.