Demand is the quantity of a good that buyers wish to buy at each price. Other things equal, at low prices the demanded quantity is higher. Supply is the quantity of a good that sellers wish to sell at each price. Oth¬er things equal, when prices are high, the supplied quantity is high as well. The market is in equilibrium when the price regulates the quantity supplied by producers and the quantity demanded by consumers. When prices are not so high as the equilibrium price, there is excess demand (shortage) raising the price. At prices above the equilibrium price, there is excess supply (surplus) reducing the price. There are some factors influencing demand tor a good, such as the prices of other goods, consumer incomes and some others.