South America has a variety of natural resources including forests, water, minerals, and fertile land for agriculture. Forest resources provide lumber and materials for industries. Water resources include rivers for hydroelectric power, irrigation, and transportation. Important minerals mined include iron, copper, tin, and oil. Major industries have developed around agriculture, mining, and oil production. Transportation networks are less developed in the mountainous west and sparsely populated interior. The population of 387 million is unevenly distributed among the twelve countries and includes people of European, indigenous, and African descent.