A dense group of bacteria that are difficult to treat with antibiotics is called

A. a biofilm.

B. lysogenic.

C. a plasmid conjugate.

D. parasitic.

A

Explanation:

Biofilms are a colony of bacteria that secrete a layer of extracellular matrix (made of polymeric substances of proteins or polysaccharides) that is hard to penetrate with antibiotics. The bacteria in the biofilm also function in coordination and are able to adapt to different factors hence making them hard to eradicate. They can be found in the inside surface of sewage pipes.