The activities of the Tertiary sector help in the development of the Primary Sector and the Secondary Sector. Goods that are produced by the Primary Sector and the Secondary Sector have to be transported and sold in shops. Transfer of money (Banking) and transfer of messages (Communication) are also very essential for the development of the Primary and the Secondary Sector. So, transportation, communication, banking and trade are some of the activities of the Tertiary sector.
There is also another division to the Tertiary sector, which is called the essential services. Activities of doctors, teachers, barbers, tailors, cobblers, administrators and IT professionals are called essential services.
The Tertiary Sector is also called the Service Sector.