Answer:
they have no cell walls.
Step-by-step explanation:
Mycoplasmas that belong to Firmicutes are considered as pleomorphic because they have no cell walls in their structure. Mycoplasmas have the following characteristics i.e. the smallest mycoplasmas are 125–250 nm in size, they are highly pleomorphic because they lack a rigid cell wall and instead of cell wall they are bounded by a triple-layered “unit membrane” that contains a sterol in its structure.