Suppose that a perfectly competitive industry is in long-run equilibrium. every firm is producing at minimum average total cost, and all firms are identical. demand in this industry decreases. which of the following will not occur in the short run? firms will exit the industry. the price will fall. firms will produce less. profits will be negative. the industry will produce less. which of the following will occur in the long run? the price will stay below the original price. existing firms will produce less. the long run supply curve will shift. firms will exit the industry. industry quantity will not change.