Interdependance between the primary sector and secondary sector :
Though economic activities are grouped into three different sectors, they are highly interdependent and complementary to each other. The development of one sector depends on the other.
For example, the primary sector (mainly agricultural sector) gets many agricultural inputs such as fertilisers, pesticides, pump sets, tractors, etc., from the secondary sector. And secondary sector (industrial sector) also gets supply of raw materials such as cotton, jute, sugarcane, oilseeds, wool, etc., from the primary sector.
Similarly, both the primary and secondary sectors depend on the tertiary sector for services such as transport and communication services, banking and insurance factilities, etc. In its turn, tertiary sector also depends on the primary sector for food and on the secondary sector for computers, calculators, trucks, stationery, etc.