The oxygenated hydrocarbons may originate from {HEAD ~ any source}, but are preferably derived from {TAIL ~ biomass} 
The oxygenated hydrocarbons may originate from { HEAD ~ any source } , but are preferably derived from { TAIL ~ biomass }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL