{HEAD ~ The method} also allows for {TAIL ~ the identification} of nucleic acids that have facilitating activities as measured by their ability to facilitate formation of a covalent bond between the nucleic acid, including its associated functional unit, and its target 
allows for
{ HEAD ~ The method } also allows for { TAIL ~ the identification } of nucleic acids that have facilitating activities as measured by their ability to facilitate formation of a covalent bond between the nucleic acid , including its associated functional unit , and its target
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH