The document discusses different types of market structures: perfect competition, monopoly, monopolistic competition, and oligopoly. It provides features and examples of each. Perfect competition is characterized by many small firms and buyers/sellers, homogeneous goods, free entry and exit. Examples include street food and fish markets. A monopoly has a single seller, barriers to entry, and products without close substitutes. Examples given are Indian Railways and aircraft production. Monopolistic competition has many buyers/sellers, product differentiation, and free entry/exit. Soap brands are used as an example. Oligopoly is dominated by a small number of large firms in an industry with high barriers to entry and interdependence between companies. Industries like cars