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:Eicosanoids can have potent biological affects that include modulation of cellular replication and sensitivity to apoptosis.(33,40) Their production is dependent on expression of specific enzymes and the relative abundance of PUFA substrate, which we clearly modified with our experimental diets.
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