Indicate whether the following statements are TRUE or FALSE. Provide a brief explanation using the relevant theory.

1. In the Keynesian system, output is determined exclusively by aggregate demand.
2. In the simple Keynesian model, investment shock affects output, employment, prices, wages and the interest rate.
3. In the Keynesian system, monetary policy effectiveness increases when interest elasticity of money demand is reduced, and fiscal policy is more effective the higher the interest elasticity of money demand.

Please help me with these questions. Each are worth 5 marks.