What represents a change in quantity demanded at different prices?

A movement along the demand curve represents a change in quantity demanded at different price levels. When the price of a good changes, the quantity demanded changes correspondingly, leading to a movement along the existing demand curve. This means that as price decreases, the quantity demanded typically increases, and vice versa, reflecting the law of demand.

In contrast, a shift in the demand curve would indicate a change in demand itself due to factors other than price, such as changes in consumer income, preferences, or the prices of related goods. Concepts like elastic demand and price elasticity of demand involve the responsiveness of quantity demanded to price changes but do not specifically illustrate the relationship of changes in quantity demanded at varying price levels.