#agent  an active and efficient cause; capable of producing a certain effect; "their research uncovered new disease agents"
  subtype:  vasoconstrictor  eliminator  impairer  mutagen  quickener  relaxer  repressor  satisfier  shortener  stressor  teratogen  vector.agent  weakener
  supertype:  causal_agent__cause__causal_agency  any entity that causes events to happen
     supertype:  thing_playing_some_role  category to classify things according to roles/viewpoints; classification under this category is application-dependant
        supertype:  thing__something___T__t___3D_or_4D_thing_or_anything_else  any category (type or individual) is instance of this type; any type is also a subtype of this type

No statement uses or specializes agent; click here to add one.