The given statement is correct. Both the blades of a pair of scissors are equally important to cut a piece of cloth. Similarly, both demand and supply are needed for determining price in the market. There is no use for demand for a product if there is no supply for the product and supply is not needed if there is no demand for a product. One of the two may play more active role in price determination in the short run. But, both are needed to determine the price in the long run.