Final answer:
A demand curve reflects the relationship between quantity and price, assuming all other factors are constant.
Step-by-step explanation:
A demand curve reflects the relationship between the quantity of a good or service that consumers are willing and able to buy at different prices. It represents the consumer's demand for a product when other economic factors are held constant. However, a demand curve does not reflect changes in these other economic factors that could affect consumer behavior, such as income, tastes and preferences, availability of substitutes, or government regulations.