Final answer:
In REA business process level modeling, resources are connected to economic events by duality associations, reflecting changes in resources due to economic events.
Step-by-step explanation:
In REA business process level modeling, resources are connected to economic events using duality associations. This link is essential for reflecting how resources change as a result of economic events. Duality says that there are direct relations between these two descriptions, that they are equivalent in a certain sense. For instance, in a sales transaction, the economic event is the sale itself and the resource could be the inventory that is being sold. The duality association connects the sale to the change in inventory, representing the decrease in inventory as a result of the sale.