1.4 Layer-3 EtherChannel
In the task:
Use a protocol that does not allow system priority configuration.
When there are more than 8 ports in an LACP LAG, LACP uses the system and port priority values to decide which ports are active and which are "standby". PAgP has no such priority, so it was used for this task to meet the requirements.
However we can configure prioity for PAgP.
From Cisco doc:
"You also can configure a single port within the group for all transmissions and use other ports for hot standby. The unused ports in the group can be swapped into operation in just a few seconds if the selected single port loses hardware-signal detection. You can configure which port is always selected for packet transmission by changing its priority with the pagp port-priority interface configuration command. The higher the priority, the more likely that the port will be selected."
Of course priority is used here for something different than in LACP but I think question is not very precise or am i missing something?