Describe the difference in market structure between monopoly and oligo

Describe the difference in market structure between monopoly and oligopoly.

What will be an ideal response?

ANSWER

Monopoly has only one producer because the product is unique, or has no close substitutes, or government gives it the exclusive authority to produce and sell that product.

Oligopoly has relatively few large firms producing standardized or differentiated products, but for which entry into or exit from the industry is very difficult, so that they are mutually interdependent in their pricing-output decisions.