When there is monopoly, a single producer or seller controls the entire market. There are no substitutes for his product. He controls the entire supply and he can fix the price. He is the finn and he also constitutes the industry. It is a one-firm industry. Thus, un- dcr monopoly, the distinction between the linn and industry disappears. TIle average revenue (AR) curve (or the demand curve) always slopes downwards to the right as in monopoly competition, but it is less elastic in monopoly than in monopolistic competition. In monopoly, there is no need to differentiate products because no dose substitutes arc available. It is one product, homogeneous ami completely under the control of the monopolist.