Perfect Competition:A market structure where firms are price takers because they are small relative to the overall market and cannot influence the equilibrium price.
Demand Elasticity: The responsiveness of quantity demanded to changes in price. Perfectly elastic demand, a characteristic of price takers, means the quantity demanded changes infinitely in response to any price change.
Marginal Revenue:The additional revenue a firm earns by selling one more unit of a good. For price takers, marginal revenue is equal to the market price since they cannot affect the price.