What is a monopoly? Why is monopoly considered as a market failure?

What will be an ideal response?

A monopoly is a situation in which a single firm controls the production, distribution, or sale of a particular product, which forces all others out of business and prevents new competitors from entering the market. A monopoly is a market failure, because in the absence of competition, one firm can set prices for its product above what a competitive free market would allow. Under these circumstances members of a society are limited in their access to that product or service and when this occurs, the monopolistic firm profits, but consumers lose.