For each of the drop down menus, choose the answer that makes the following statement correct.

For firms in perfectly (purely) competitive markets, long run economic profits are: select answer (enter, exit, zero, shutdown, postivie, negative)

because firms will: select answer (enter, exit, zero, shutdown, postivie, negative) this market if profits are less than that and

select answer (enter, exit, zero, shutdown, postivie, negative) this market if profits are greater than that.