The regions made of magnetic material are impressed with {HEAD ~ a magnetic material} which can be erased by {TAIL ~ chemical and mechanical action} 
erased by
The regions made of magnetic material are impressed with { HEAD ~ a magnetic material } which can be erased by { TAIL ~ chemical and mechanical action }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL