Step-by-step explanation:
The value on the horizontal axis of a typical demand curve for apples represents a "Flow Variable." A flow variable measures a quantity over a specified period of time. In this case, it measures the amount of apples consumers would be willing and able to purchase in a market within a given time period (e.g., per day, per month, per year). Flow variables are typically depicted on the horizontal axis of demand and supply curves in economics.