Read the following table from your textbook CharacteristicFour Major Market StructuresPerfect CompetitionMonopolistic CompetitionOligopolyPure MonopolyNumber of firmsVery manyManyA fewOneTypes of productHomogeneousDifferentiatedHomogeneous or differentiatedHomogeneousBarriers to entry or exit from industryNo substantial barriersMinor barriersConsiderable barriersExtremely great barriersExamplesAgricultureRetail tradeBankingPublic utilitiesTake an example of a real-world company that is becoming a monopoly and explain what threats are associated with monopolies in today's world