Problem: The given is a complete and correct definition of the demand curve for commodity X. The demand curve shows, for a given market:
1) How much of X would be bought at the equilibrium price.
2) How, as people's incomes rise and they have more money to spend, their purchases of X would increase.
3) How the amount of money people spend to purchase X changes as the price they must pay for it changes.
4) The amounts of X that would be bought each period, at each and any price, assuming other factors influencing demand (incomes, tastes, etc.) remain constant.
5) The amounts of X that would be bought each period if taxes were to go down.