Defines and explains a closed system and provides an example. Defines and explains an open system and provides an example. Explains the inner and outer flows of a closed system. Explains the inner and outer flows of an open system. Defines and explains leakages in an open system. Defines and explains injections in an open system. Provides a personal example of a leakage describes it and explains it. Provides a personal example of an injection describes it and explains it.