{HEAD ~ X rays}, for instance, are absorbed to differing degrees by different internal organs, and to {TAIL ~ the greatest degree} by bones 
are absorbed to
{ HEAD ~ X rays } , for instance , are absorbed to differing degrees by different internal organs , and to { TAIL ~ the greatest degree } by bones
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH