The primary sector includes all activities that are associated with the use of natural resources like agriculture, fishing, forestry etc. The secondary sector is concerned with the processing of raw materials into products and goods. Without the secondary sector, the primary sector would not have a market for selling their products and thereby earn income. For example, agricultural production of sugarcane is a primary sector activity. But without a secondary sector activity like mills which buy the sugarcane and process it for sugar, the sugarcane would rot, and farmers would stop production of the same.