This document discusses the four main types of industries: primary, secondary, tertiary, and quaternary. Primary industries involve activities like farming, fishing, forestry and mining that directly use natural resources. Secondary industries process and transform raw materials from primary industries into manufactured goods. Tertiary industries provide services like transportation, banking, tourism and retail. Quaternary industries handle information and knowledge through activities such as research and development. The document provides examples for each type and discusses how industries are classified based on factors like labor intensity.