Which term best describes a system that exchanges energy and matter with its surroundings?

Which term best describes a system that exchanges energy and matter with its surroundings?

• A. Closed System
• B. Open System
• C. Biosphere
• D. Percolation

Answer: (B)

When a system exchanges both energy and matter with its surroundings, it is described as an open system. In hydrology, this means the boundary of the system allows water or other substances to cross it (mass transfer) and also permits energy transfer, such as heat or radiant energy, between the system and its surroundings. For example, a drainage basin receives water from rainfall and loses water through runoff, infiltration, and evaporation, while also exchanging energy with the air and sun through heat and moisture fluxes. That combination of matter and energy crossing the boundary is what defines an open system. A closed system would allow energy to cross the boundary but not matter, which isn’t typical for natural hydrological settings. An isolated system would restrict both matter and energy exchange, an idealization not found in real basins. The term biosphere refers to the global sum of living systems and their interactions, not a specific system boundary type. Percolation describes how water moves through soil, a process within the system rather than a description of whether the system exchanges matter or energy with its surroundings.

When a system exchanges both energy and matter with its surroundings, it is described as an open system. In hydrology, this means the boundary of the system allows water or other substances to cross it (mass transfer) and also permits energy transfer, such as heat or radiant energy, between the system and its surroundings. For example, a drainage basin receives water from rainfall and loses water through runoff, infiltration, and evaporation, while also exchanging energy with the air and sun through heat and moisture fluxes. That combination of matter and energy crossing the boundary is what defines an open system.

A closed system would allow energy to cross the boundary but not matter, which isn’t typical for natural hydrological settings. An isolated system would restrict both matter and energy exchange, an idealization not found in real basins. The term biosphere refers to the global sum of living systems and their interactions, not a specific system boundary type. Percolation describes how water moves through soil, a process within the system rather than a description of whether the system exchanges matter or energy with its surroundings.