In a microbial fuel cell, {TAIL ~ the transgenic microbes} have access to {HEAD ~ a feedstock} 
In a microbial fuel cell , { TAIL ~ the transgenic microbes } have access to { HEAD ~ a feedstock }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD