**Sectors formed as per economic activities:**

The classification of economic activities into different sectors is based on the nature of the activities performed and the type of goods and services produced. There are three main sectors:

1. **Primary Sector**: This sector involves activities related to the extraction and production of natural resources. It includes activities such as farming, fishing, mining, forestry, and agriculture. The primary sector is essential as it provides raw materials for other sectors and contributes to the overall economic development of a country.

2. **Secondary Sector**: The secondary sector involves activities related to manufacturing and processing. It includes industries such as construction, manufacturing, electricity generation, and refining. This sector transforms raw materials obtained from the primary sector into finished goods. The secondary sector plays a crucial role in industrialization and creates employment opportunities.

3. **Tertiary Sector**: The tertiary sector is also known as the service sector. It involves activities that provide services to individuals and businesses. This sector includes industries such as healthcare, education, transportation, banking, tourism, and retail. The tertiary sector contributes significantly to the economy as it meets the various needs and demands of the population.

**Usefulness of classification into different sectors:**

The classification of economic activities into different sectors is useful for several reasons:

1. **Policy-making and planning**: It helps policymakers and governments to formulate appropriate policies and plans for the development of different sectors. They can allocate resources, set targets, and implement strategies to promote growth and address sector-specific challenges.

2. **Employment opportunities**: The sector classification helps in identifying the sectors that have the potential to generate more employment opportunities. This information is valuable for policymakers, educators, and individuals seeking employment, as it allows them to make informed decisions about job prospects and career choices.

3. **Economic analysis**: The classification of economic activities into sectors enables economists and researchers to analyze the overall performance of the economy and understand the interdependencies between sectors. It helps in measuring economic growth, productivity, and contributions of different sectors to the Gross Domestic Product (GDP).

4. **Resource allocation**: The classification allows for efficient allocation of resources. By knowing which sectors require more resources, policymakers can allocate funds, infrastructure, and manpower accordingly. This ensures optimal utilization of resources and promotes balanced development across sectors.

5. **International trade and investment**: The sector classification provides a framework for analyzing international trade patterns. It helps identify the sectors in which a country has a comparative advantage and can specialize in for export. This information is useful for attracting foreign investment and fostering international trade relationships.

In conclusion, the classification of economic activities into different sectors is crucial for understanding the structure and functioning of an economy. It facilitates policy-making, resource allocation, employment generation, economic analysis, and international trade. The sector classification provides a comprehensive framework for assessing and promoting economic development.