Complete the following table.

Explain the ‘Free entry and exit of firms’ feature of monopolistic competition.

When price of a commodity X falls by 10%, its demand rises from 150 units to 180 units. Calculate its price elasticity of demand. How much should be the percentage fall in its price so that its demand rises from 150 to 210 units?

Good Y is a substitute of good X. The price of Y falls. Explain the chain of effects of this change in the market of X.

Explain the chain of effects of excess supply of a good on its equilibrium price.