Legal drinking age. The legal drinking age is the age at which a person can legally consume or purchase alcoholic beverages. These laws cover a wide range of issues and behaviors, addressing when and where alcohol can be consumed.
An open system is a system that has external interactions. Such interactions can take the form of information, energy, or material transfers into or out of the system boundary, depending on the discipline which defines the concept.
Definition of closed system: An isolated system that has no interaction with its external environment. Closed systems with outputs are knowable only thorough their outputs which are not dependent on the system being a closed or ...