In which type of system can matter flow in and out freely?

In an open system, matter can flow freely in and out of the system, allowing exchange with the surrounding environment. This type of system enables the input of materials from outside and the output of materials to the surroundings, which is essential in various natural processes and human-made systems. For example, in ecological studies, ecosystems are often considered open systems because they exchange energy and matter with their surroundings, such as plants taking in carbon dioxide and water, while animals release waste products.

In contrast, other system types restrict matter flow. Closed systems do not allow matter to enter or leave, although energy can be exchanged. Isolated systems prevent both matter and energy exchange. Static systems typically refer to systems that do not change over time, and they may or may not allow matter exchange depending on their specific context. The definition of an open system is central to understanding processes in fields like biology, environmental science, and thermodynamics, where interactions and exchanges are fundamental.