Resources, abilities or other game elements are exchanged between players, either between each other or the system.

Players exchange some kind of Resource, be it information, actions, or game elements, between each other or the game system.

Are their resources of some kind which can be exchanged between players or the game?

What kind of resources can be traded, is there an exchange value? You can motivate trading behaviours by using an asymmetrical distribution reward, stimulating players to trade with each other.