One assumption of the perfectly competitive model is free entry and exit. this assumption most directly leads to the implication that positive economic profit is only possible in the short run.
Profit is the difference between the return an economic agent earns from its output and the opportunity cost of its input. It equals total revenue minus total costs (including explicit and implicit costs).
Economic profit or loss is the difference between the revenue from the sale of output and the cost and opportunity cost of all inputs used. Opportunity cost and explicit cost are subtracted from earned revenue when calculating economic profit.
Learn more about economic profit here: brainly.com/question/24477585
#SPJ4
The correct answer would be: checks & balances
