its urgent

(2.2 \"Costs play a key role in determining theoretically the optimum level of production". Explain the statement. {23 Show that normal goods have a positive value of income elasticity of demand and inferior goods have a negative value of income elasticity of demand? QA 'Given that the future is unlmown, the best we can do is to estimate the likelihood of future events and then use expected prot as the decision criterion.' Discuss