Answer: A group of bacteria that accumulate in layers and secrete an protective extracellular material
Step-by-step explanation:
Biofilm comprises any spectrum of microorganisms, including pathogens in which cells stick to each other and to a surface, so they become adherent cells. These cells become embedded within an extracellular matrix that is composed of extracellular polymeric substances (polysaccharides, lipids, proteins and DNA) which surrounds and protects cells. For this reason, bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics.