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.
An operating system is a program designed to run other programs on a computer. A computerâs operating system is its most important program.esktop PC. Multitasking operating systems can run more than one program at the same time. A computer's operating system is one of its most important aspects. An operating system can be used to managed files on a computer hard drive. A central processing unit.