Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Lemurs provide an interesting case for evaluating the predictions of this hypothesis because they possess many anatomical and behavioral traits thought to have evolved for exactly this purpose: energy conservation and risk minimization (Wright 1999; Jolly 1966).
Category: