Sectors of the economy Economic activity is usually divided into 3 sectors: 1. Primary industry – involves extracting raw materials. When economies first start growing they are heavily dependent on their own raw materials – e.g. coal, iron ore and other metals that are useful in manufacturing processes. 2. As economies industrialise, secondary industries grow – consisting of construction and manufacturing such as car factories. These use the output of primary industry to produce semi-finished and finished goods – chocolate products, clothing, homes, etc. 3….