Answer:
The correct answer is "open" systems.
Step-by-step explanation:
The correct answer is "open" systems.
Natural ecosystems are open systems, which means that they exchange matter and energy with their surroundings. They are not closed or isolated from their environment, but instead interact with it through various inputs and outputs. This allows ecosystems to maintain a dynamic equilibrium with their environment, adapting to changes and responding to disturbances.
In contrast, closed systems are isolated from their surroundings and do not exchange matter or energy with the outside world. Linear, cylindrical, and circular are not terms that are commonly used to describe natural ecosystems or their properties.