**Primary Sector:**
The primary sector is the first stage of economic activity and involves the extraction and production of raw materials directly from nature. It includes activities such as farming, fishing, mining, forestry, and hunting. This sector is also known as the agricultural and extractive sector.

**Secondary Sector:**
The secondary sector is the second stage of economic activity and involves the processing and manufacturing of raw materials obtained from the primary sector. It includes activities such as manufacturing, construction, and energy production. This sector is also known as the industrial sector.

**Tertiary Sector:**
The tertiary sector is the third stage of economic activity and involves the provision of services to individuals and businesses. It includes activities such as healthcare, education, transportation, finance, tourism, and retail. This sector is also known as the service sector.

**Explanation:**

**Primary Sector:**
- The primary sector is primarily focused on the extraction of natural resources from the environment.
- It involves activities like farming, where crops are grown and harvested, and livestock is raised for food production.
- It also includes mining, where minerals and ores are extracted from the earth, and forestry, where timber and wood products are obtained from forests.
- Fishing and hunting are also part of the primary sector, as they involve the capture of fish and wild animals.
- The primary sector provides the raw materials necessary for the production and manufacturing processes in the secondary sector.

**Secondary Sector:**
- The secondary sector involves the transformation of raw materials obtained from the primary sector into finished goods.
- Manufacturing is a significant activity in this sector, where raw materials are processed and converted into products through various industrial processes.
- Construction is another important activity in the secondary sector, where buildings and infrastructure are constructed using materials like cement, steel, and bricks.
- Energy production, such as the generation of electricity from coal, oil, or renewable sources, is also part of the secondary sector.
- The secondary sector adds value to the raw materials by processing and transforming them into usable products.

**Tertiary Sector:**
- The tertiary sector focuses on providing services to individuals and businesses.
- It includes various activities such as healthcare, where medical professionals provide treatment and care to patients.
- Education is also part of the tertiary sector, involving the provision of knowledge and skills through schools, colleges, and universities.
- Transportation services, such as road, rail, air, and sea transport, are essential for the movement of goods and people.
- The finance sector, including banking, insurance, and investment services, plays a crucial role in managing and allocating funds.
- Tourism and hospitality services, retail, and entertainment are also part of the tertiary sector, catering to the needs and desires of consumers.
- The tertiary sector contributes significantly to the economy in terms of employment generation and revenue generation.

In conclusion, the primary sector involves the extraction of raw materials, the secondary sector involves the processing and manufacturing of those raw materials, and the tertiary sector involves the provision of services. These sectors are interconnected and play a vital role in the overall economic development of a country.

Hii.. The major difference is that activities of Tertiary sector do not produce a good but work on the goods produced by agriculture (Primary) and secondary sector