Answer:
Legionella tends to form biofilms and infect other microbial cells as intracellular pathogens.
Step-by-step explanation:
The Legionella genus of the bacteria is a group of gram-negative bacteria that can cause legionnaires disease.
The Legionella pneumophila is a species of this genus which can cause legion pneumonia. The bacteria lives in the freshwater and is resistant to chemical treatment like chlorine and the biocide treatment.
The reason for this resistance is since this species form a polysaccharide layer around the colony of the bacteria which is resistant to these treatments and also the bacteria prove parasitic to the protozoans which feed on these bacteria.
Thus, the selected option is the correct answer.