Ans.
Bacterial cells are simple prokaryotic cells, made up of capsule, cell membrane, cell wall, cytoplasm, ribosomes, and nucleic acid. The structure that protects the bacteria under harsh conditions, such as high acidic environment of stomach and help them to infect hosts is known as slime layer or capsule.
It is made up of polysaccharide molecules and enhances the ability to cause disease (virulence) of bacteria.
Thus, the correct answer is 'capsule.'
