In dividing economic activities into primary, secondary and tertiary sectors, the criterion used is ____________.
There are four basic categories of economic activities: The Primary Sector that is raw materials. The Secondary Sector, which comprises industry and manufacturing. The Tertiary Sector that is services. The Quaternary Sector, which we also appeal to the 'knowledge sector. Economic activities are classified as primary, secondary and tertiary activities on the basis of nature of activity that is undertaken.