economics
The word 'économie' is used in French to refer both to the economic system (just like in English) and to the academic discipline that studies it. It is a feminine noun, so it is used with the definite articles 'la'. For instance, 'La économie est importante'.
Economics is a complex social science.
This sentence is stating the fact that the subject of economics is complex and falls under the category of social sciences.
Globalization affects the economy in various ways.
This sentence implies the impact of globalization, which includes changes worldwide such as in culture, international relations, and technology, on the economics of countries or the world.
He is studying economics at the university.
In this sentence, the subject is informing that a person (he) is studying the subject of economics at a higher-level educational institution, a university.