Answer: The correct answer for the blank is -
Genetic makeup and biochemistry of their cell wall.
Explanation:
Archaea and Eubacteria are the two different domains of prokaryotes (organisms that are devoid of true nucleus and membrane bound subcellular compartments).
They have different genetic makeup and biochemistry.
The cell wall of Eubacteria is made up of peptidoglycan along with lipopolysaccharide. They possess lipid membrane with ester bonds with fatty acids.
On the contrary, Archaea (that are found in harsh environments like hotsprings), lack peptidoglycan in their cell wall.
They have ether bonds that connects lipids to the glycerol in their membrane.
