In a pure communist regime of government, it would soon fall into a state of chaos. Proven by every communist government, food would be scarce due to many workers' unmotivated lives. Workers would not want to work anymore because there is no reward for them when slaving in factories and farms. With no motivation to work, production will dramatically slow causing a collapse of the economy. People do not enjoy their lives being run by the government as well, which is why they revolt against communist oppression (not for it).
The correct answer is government. Here in the United States, to fill the purpose of government we have things such as the Navy, Air Force and other military branches.
