Which industries are part of the Tertiary industry?

• A. Quaternary and Quinary
• B. Primary and Secondary
• C. Tertiary and Quaternary
• D. All five industries

Answer: (A)

Economies categorize activity by type, and the Tertiary sector consists of services—things people do for others rather than produce physical goods. In many modern frameworks this sector is further broken down into knowledge-based and high-level service activities, known as the quaternary and quinary sectors. Since these knowledge and decision-making services are part of the service economy, they are considered within the broader Tertiary category. Primary and Secondary refer to extraction and manufacturing, not services, so they aren’t part of the Tertiary. Saying all five sectors would mix different kinds of activity that belong to separate groups. Therefore, the industries that belong to the Tertiary sector in this framework are quaternary and quinary.