Bronfenbrenner's ecological systems theory explains how different environments influence human development. It consists of five layers: the microsystem, which includes immediate surroundings like family and school; the mesosystem, which connects different microsystems; the exosystem, which involves external settings that indirectly affect the individual; the macrosystem, which encompasses broader cultural and societal influences; and the chronosystem, which considers the dimension of time and life transitions. This theory emphasizes that development is not just shaped by individual traits but also by interactions within these various systems. Understanding these layers helps researchers and educators recognize the complex factors that impact a person's growth and behavior throughout their life.