What type of action requires the energy from the discharged cartridge to cycle itself?

In firearms, actions generally refer to the mechanisms that load, fire, and eject cartridges. Both recoil-operated and blowback-operated actions use the energy generated from the discharged cartridge to cycle the firearm.

Recoil-operated actions rely on the backward movement of the entire firearm or a portion of it when the cartridge is fired. This movement harnesses the energy of the discharged cartridge to eject the spent casing and chamber a new round.

On the other hand, blowback-operated actions utilize the force of the expanding gases created during firing to push the bolt or slide backward directly. This movement, driven by the pressure generated from the primer and gunpowder, allows the action to eject the spent cartridge case and load another round from the magazine.

Selecting both recoil and blowback as correct captures the fundamental principle that both mechanisms depend on the energy from the discharged cartridge to function effectively. Therefore, it is valid to state that both recoil-operated and blowback-operated actions fit the description provided in the question.