The AR curve and industry demand curve are the same in case of Monopoly.

Explanation:
In economics, the average revenue (AR) curve represents the average revenue earned by a firm per unit of output sold. It is calculated by dividing the total revenue (TR) by the quantity of output sold (Q). The industry demand curve, on the other hand, represents the total quantity of a good or service that all firms in the industry are willing and able to sell at each possible price.

In a monopoly market structure, there is only one firm that dominates the entire industry. This firm has complete control over the supply of the product and faces the industry demand curve as its demand curve. As a result, the AR curve and industry demand curve are the same in case of a monopoly.

Reasons for the similarity between the AR curve and industry demand curve in a monopoly:

1. Single Seller: In a monopoly, there is only one seller in the market. This firm has the ability to set the price of the product and the quantity to be supplied. Since there are no other sellers in the market, the industry demand curve is essentially the demand curve faced by the monopolist.

2. Price Maker: As the sole producer in the market, the monopolist has the power to determine the price at which the product is sold. The monopolist sets the price based on the level of output it wants to produce and the corresponding demand for the product. This means that the AR curve for the monopolist is the same as the industry demand curve.

3. No Substitutes: In a monopoly, there are no close substitutes for the product being sold. Consumers have no alternative but to purchase the product from the monopolist at the price set by the firm. This gives the monopolist significant control over the market and allows it to face the entire industry demand curve.

4. Barriers to Entry: Monopolies often arise due to barriers to entry, which prevent new firms from entering the market and competing with the monopolist. These barriers can include factors such as patents, exclusive access to resources, or high start-up costs. The absence of competition allows the monopolist to face the entire industry demand curve.

Overall, in a monopoly market structure, the AR curve and industry demand curve are the same because the monopolist has control over the price and quantity of output sold, and there are no other firms in the market to compete with.