Final answer:
Economists use the term demand to refer to the amount of some good or service consumers are willing and able to purchase at each price, based on needs, wants, and ability to pay. Price changes can impact demand.
Step-by-step explanation:
Economists use the term demand to refer to the amount of some good or service consumers are willing and able to purchase at each price. Demand is fundamentally based on needs and wants-if you have no need or want for something, you won't buy it. From an economist's perspective, needs and wants are the same thing. Demand is also based on ability to pay. If you cannot pay for it, you have no effective demand.
For example, if the price of a concert ticket is too high, some people may decide they don't need or want to attend the concert, reducing the demand. Conversely, if the price of a product decreases, more people may find it affordable and increase their demand for it.