The size of a nation’s economy is commonly expressed as its:

The size of a nation's economy is commonly expressed as its:
Answer: Gross Domestic Product (GDP)

Gross Domestic Product (GDP) measures a nation’s economic size, reflecting the total value of goods and services produced. Studying GDP highlights its role in economic analysis, the challenges of accurate measurement, and its impact on policy-making. It also offers insights into how economies are compared, providing lessons on using economic indicators to guide development and fiscal strategies effectively.