Which of the following are characteristics of a monopoly market? (Check all that apply.) Question 4 options: If P < ATC, firms will shutdown in short run If P < AVC, firms will shutdown in short run In the short run, positive economic profit possible Firms face a perfectly elastic demand curve Firms sell homogeneous products Firms are interdependent and behave strategically Firms face a downward sloping demand curve In the short run, only zero economic profit possible Firms sell differentiated products Firms make independent decisions