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.
systems analysis - analysis of all aspects of a project along with ways to collect information about the operation of its parts. analytic thinking, analysis - the abstract separation of a whole into its constituent parts in order to study the parts and their relations.