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It might not be included in a diagram that's provided to you. Basically, a salt bridge just helps to keep electrons flowing throughout the cell. Without a salt bridge, the electrons would flow from anode to cathode and would build up in the cathode portion. Eventually, since all the electrons are already on the cathode side, the reaction will stop because no more electrons will want to go to the side that already has too many electrons.The salt bridge just pushes electrons back from the cathode to the anode so that we get a consistent voltage going on all the time (at least until the reaction runs out). Keep in mind that the anode metal gets consumed in the process, so even if we have electrons consistently flowing throughout the cell, the reaction will have to eventually end when there is no more anode metal left.
Even if the diagram does not show a salt bridge, I think it is safe to assume that there is a salt bridge in all redox reactions. If there were no salt bridge there would be a buildup of elections in the cathode and after a certain point, electron flow would stop because of the charge buildup. By having a salt bridge we are preventing this electron repulsion and allowing the redox reaction to continue.
If there was no salt bridge, the reaction would simply stop as there would be no replenishment electrons on the anode side. A salt bridge is present in pretty much all the problems we deal with because it keeps the reaction going for us to analyze.