Solution

Oligopoly- there are many buyers but few sellers. •       Oligopsony- is a market form in which the number of buyers is small while the number of sellers in theory could be large. •       Perfect Market - a theoretical market in which buyers and sellers are so numerous and well informed that monopoly is absent and market prices cannot be manipulated. •       Duopoly -A duopoly is a type of oligopoly where two firms have dominant or exclusive control over a market. It is the most commonly studied form of oligopoly due to its simplicity. •       Monopsony-a monopsony is a market structure in which a single buyer substantially controls the market as the major purchaser of goods and services offered by many would-be sellers.