Compare perfect competition, monopolistic competition, oligopoly and monopoly.

1. 1 · Introduce market structure. Markets differ by number of firms, type of product, ease of entry and control over price.
2. 2 · Perfect competition and monopoly in brief. The two extremes: many price takers with normal profit versus one price maker with supernormal profit.
3. 3 · Monopolistic competition. Many firms, differentiated products, free entry; long-run tangency with normal profit and excess capacity.
4. 4 · Draw its long-run equilibrium. [Diagram: downward-sloping AR tangent to the falling part of ATC; MR = MC at the same output]
5. 5 · Oligopoly. Few firms, interdependence; kinked demand curve and price rigidity; collusion and non-price competition; the prisoners' dilemma.
6. 6 · Comparison table. Firms, product, entry, price control, long-run profit, efficiency, examples.
7. 7 · Sri Lankan business link. Tea smallholders (near-perfect competition), restaurants (monopolistic competition), mobile telecom (oligopoly), electricity grid (monopoly).
8. 8 · Conclude. As we move from perfect competition to monopoly, firms gain price power and efficiency usually falls.

Scoring tip: A four-column comparison table with one Sri Lankan example per structure can earn half the marks on its own.