Identify the basic characteristics of monopoly, oligopoly, monopolistic competition, and pure competition

 Monopoly

One firm

Complete barrier to entry

Total control over price

One product

 

Oligopoly

2-3 firms

High barrier to entry

Control majority of output

Similar/identical products

 Monopolistic Competition

Many Firms

Few artificial barriers to entry

Slight control over price

Differentiated products

 

Perfect (Pure) Competition

Many Buyers and Sellers

Identical Products

Informed Buyers and Sellers

Free Market Entry and Exit