Territories may be defended by:
Groups or individuals reflects key principle in quiz on territory behaviour+pyqs, where evolutionary mechanisms shape genetic variation and adaptation. In this context, Groups or individuals aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why Groups or individuals fits helps integrate natural selection, environment.
Ref: Krebs & Davies, Behavioural Ecology, Chapter 5: Territoriality.