Bacteria naturally prefer company instead of solitude for growth. Examples of this kind of communal growth pattern can be found everywhere, from surfaces of the teeth and the intestines, to the surface of a slimy rock in the lake, to the thick floc that clogs water pipes. These examples of communal bacterial growth are known by what name?
A) infectious unit
B) colony
C) biofilm
D) planktonic unit

The correct option is (C). The above mentioned definition is true for biofilm that resembles a slimy structure composed of cells attached to each other.

Explanation:

 The adherent cells that results due to the formation of biofilm are known to invade the slimy extracellular matrix that are made up of extracellular polymeric substances. These embedded cells serves the function of production of EPS component that is composed of genetic material, polysaccharides and lipids. These biofilms are capable of growth on the living as well as the non living things.  

Formation of biofilm by the microbes occurs due to several factors namely nutritional factors, antibiotic attack and cellular recognition to the attachment site. The defined steps of the biofilm formation includes initial attachment, Irreversible attachment, Maturation I, Maturation II and Dispersion.

the answer is d (apex) good luck : ))

amber has allowed scientists to study dna that has been preserved over millions of years.