{HEAD ~ The presence} of {TAIL ~ various different microorganisms} in a single culture is generally referred to as a mixed culture 
{ HEAD ~ The presence } of { TAIL ~ various different microorganisms } in a single culture is generally referred to as a mixed culture
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH