Answer:
Changes in demand are those that occur due to price while everything else is held constant. These changes are represented by a movement along the demand curve.
Changes in quantity demanded are those that occur due to factors other than price, for example: variations in consumers preferences, seasonality of goods, or income rises. These changes are represented by a shift of the demand curve, either to the right, representing more quantity demanded at any given price, or shifts to the left, representing less quantity demanded at any given price.