What is meant by a movement along a demand curve?

A movement along a demand curve refers specifically to a change in the quantity demanded of a good or service resulting from a change in its price, while all other factors remain constant. This relationship is depicted on a demand curve, where the curve itself represents the demand for a product based on different price levels.

When the price decreases, consumers tend to purchase more of a good or service, leading to an increase in the quantity demanded, which is represented by a downward movement along the demand curve. Conversely, if the price increases, the quantity demanded decreases, leading to an upward movement along the curve. This illustrates the law of demand: as price falls, quantity demanded rises, and vice versa.

The other options describe different economic phenomena not related to movements along the demand curve. Changes in consumer preferences, shifts in the demand for related goods, or overall increases in market demand involve shifts of the entire demand curve rather than movements along it.