In the circular flow of expenditure and income, why must the total value of production in an economy equal the total value of income?

Because every transaction has a buyer and a seller

Explanation:

Because every transaction has a buyer and a seller, every penny spent on a good or service must end up as someone's income.

The economy seem to operate in a circular motion as illustrated in the circular flow diagram. Economists use this diagram to demonstrate how the economy of a nation operates, by demonstrating how money, services and goods navigate in the economy.  

answer; /// i believe the correct answers are (b) change in population and (e) future expectation of check first, good luck

answer; i believe that the correct answer is ( secondary research); //