the contribution to productive activity made by land (for example, a factory site or farm) and basic raw materials, such as iron ore, timber, oil, corn, etc. Some natural resources, such as wheat, are renewable, while others, such as iron ore, are finite (non-renewable) and will eventually be exhausted. However, as stocks of non-renewable natural resources begin to deplete, their price will tend to rise, providing an incentive to seek other natural or synthetic substitutes for them. Natural resources are one of the three main FACTORS OF PRODUCTION, the other two being LABOUR and CAPITAL. See ECONOMIC GROWTH.