Econ 2100 (summer 2015 sections 07 & 08) ___________________ is a market structure in which there is one single seller of a unique good (with no close substitutes ) and in which there are barriers to entry which prevent rival firms from entering the market. More than one (perhaps all) of the above answers are correct. New firms will enter a monopolistically competitive firm in the long run if for the typical firm in the short run price is greater than average total costs of production. In the short run, the only variable input which company x hires is labor. When increasing the amount of labor hired from. 80 units to 81, output increases from 1,200 units to 1,210 units. If the production process of this firm is such that the marginal product of labor is diminishing, then _______ units of output would be produced if 82 units of labor were hired. more than 1,210 but fewer than 1,220.