Bionomics (7)
I believe the answer is:
ecology
'bionomics' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for ecology that I've seen before include "Science to do with the relationship between living things" , "The environment as it relates to living organisms" , "Science of the interaction of organisms and their environment" , "Green study or movement" , "Green science" .)