Step 1: Understanding the Concept:
Sociology is a distinct branch of social science established to study human social life, groups, and societies systematically.
Step 3: Detailed Explanation:
- The study of individual behavior in society falls primarily under the domain of Social Psychology.
- The study of economic systems, resources, and markets is the focus of Economics.
- The study of past events and historical social changes belongs to the field of History.
- Sociology is defined as the scientific study of social interactions, social relationships, collective social behavior, and the various institutions (such as family, religion, and education) that structure a society.
Step 4: Final Answer
Thus, sociology is correctly defined as the study of societal institutions and social relationships.