Which aspect is NOT typically studied within the context of sociology?

Sociology focuses on the study of human social behavior, social institutions, and the structures that influence societal interactions. This includes investigating social behavior and the dynamics within various groups, organizations, and societies. Economic systems also fall under the purview of sociological study, as they significantly affect social structures and relationships, exploring how economic factors influence social inequality, class structures, and community interactions.

In contrast, geological formations and bird migration patterns are primarily areas of study within the fields of geology and biology, respectively. Geological formations examine the Earth's physical structure and processes, while bird migration patterns involve ecological and biological studies of animal behavior. These topics do not typically engage with social structures or human interactions, which are central to sociological inquiry. Thus, the reason geological formations is the correct choice is that it does not pertain to the study of society or social relationships, making it outside the scope of sociology.