{HEAD ~ Such changes} may be {TAIL ~ the result} of exposure of the cells to environmental toxins 
be
{ HEAD ~ Such changes } may be { TAIL ~ the result } of exposure of the cells to environmental toxins
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH