Which of the following is true regarding this economic model? while simple, the circular-flow diagram can still be useful for the purposes of modeling how dollars and resources move throughout an economy. because, in reality, the economy is very large, the simplicity of the circular-flow diagram makes it useless for the purposes of modeling how dollars and resources move throughout an economy. because it does not take into account the role of government, the circular-flow diagram is useless for the purposes of modeling how dollars and resources move throughout an economy. because it does not take into account international trade, the circular-flow diagram is useless for the purposes of modeling how dollars and resources move throughout an economy.