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