Mononucleosis, commonly called mono, is an illness caused by the Epstein-Barr virus. Although it's rarely serious, mono can cause bothersome symptoms that last several weeks.
Complex systems. Complex systems present problems both in mathematical modelling and philosophical foundations. The study of complex systems is an approach to science that investigates how relationships between parts give rise to the collective behaviors of a system and how the system interacts and forms relationships with its environment.
Ecological systems theory. Ecological systems theory, also called development in context or human ecology theory, identifies five environmental systems with which an individual interacts. This theory provides the framework from which community psychologists study the relationships with individuals' contexts within communities and the wider society. Ecological systems theory was developed by Urie Bronfenbrenner. The theory is also commonly referred to as the ecological/systems framework.