The answer is <span>Special RNA polymerase, peptidoglycan in cell walls, ester-linked fatty acids.
Bacterial cell wall consists of peptidoglycans, not of cellulose or chitin. They also have ester-linked fatty acids, like eukaryotes. Ether-linked fatty acids are characteristics of Archaea. Also, bacteria have special RNA polymerase, unlike Eukaryotes that have three different type of RNA polymerase.</span>
The correct answer is "Special RNA polymerase, peptidoglycan in cell walls, ester-linked fatty acids".
Explanation:
There are some key markers that identify a Bacteria among other species that belong to the other two domains (Archaea and Eukarya). These key markers include: A special RNA polymerase, bacteria has a one and only special type of RNA polymerase with a single regulatory subunit and four catalytic subunits; peptidoglycan in cell walls, most bacteria have a cell wall made of peptidoglycans, which is the target for many antibiotics; ester-linked fatty acids, ester-linked fatty acids are an unique biomarker for Bacteria, while other organisms such as Archaea have ether-linked fatty acids.