Need answer for this part

QUESTION 19 A bowed out production possibilities frontier does not reflect constant opportunity. True False QUESTION 20 The third principle states that because people respond to incentives, markets move toward equilibrium. O True False QUESTION 21 Equilibrium is an economic situation in which individuals would be better off by doing something different. True False QUESTION 22 Points that exist along the production possibilities frontier are attainable but not efficient. O True False