Using an equation (or equations) answer:

1. (i)"A decrease of the marginal propensity to consume, c1, (caused for example by increased consumer pessimism as a result of the coronavirus epidemic) will cause a shift in the demand curve (or ZZ curve) and as a result, a change in the equilibrium level of production (Y) and income (Y). The change in the ZZ curve is two-fold: there is both a change in the intercept and in the slope of the ZZ curve." Discuss, making sure you draw a diagram showing how this change affects the equilibrium level of output and production. Will this change represent a movement along the IS curve or will the IS curve shift?