Answer:
In economics a demand is defined as the quantity of goods and services that customers are capable to buy and that they find desirable to buy at a particular price for that period of time .
Demand is dependent on the customer's needs and wants each customer may have different things that they consider to be needs to them and those they consider as just wants.
This also depends on affordability, if one doesn't have the money to buy the product then the demand isn't effective.
When the price of the product rises usually it's demand decreases and vice versa when the price fall the quantity of that product demanded will increase.