If cell wall was used as the only criterion for classifying organisms, then Mycoplasma would have belonged to which one of the following groups?

Mycoplasma are organisms that completely lack a cell wall.

Among the given options, animals are the only group of organisms that characteristically lack a cell wall. Plants have cell walls made of cellulose, fungi have cell walls made of chitin, and many protists also possess cell walls.

Therefore, if the presence or absence of a cell wall were the only criterion for classification, Mycoplasma would be placed in the animal group.

Answer: Animals