Final answer:
Supply shocks lead to the decreased marginal product of labour, resulting in lower real wages and output as per the real business cycle theory.
Step-by-step explanation:
According to the real business cycle theory, supply shocks decrease the marginal product of labour which causes real wages and output to decrease. This occurs because a supply shock, such as a sudden increase in energy prices, can increase production costs and reduce the profitability of producing goods and services. With higher production costs, the marginal product of labour falls, inducing firms to reduce the amount of labour they employ, which drives down both real wages and output.