Final answer:
A closed system experiences no input or output of energy or materials, unlike natural ecosystems such as deserts or rainforests, making a mass on a spring in a vacuum an example of a closed system.
Step-by-step explanation:
The type of ecological system that experiences no input or output of energy or material is referred to as a closed system. In this context, options such as deserts, rainforests, and grasslands do not fit the definition, as they all have energy and material transfers in the form of things like sunlight, water, and migration of animals. However, a theoretical construct like a mass on a spring in a vacuum behaves as a closed system where, once set in motion, no energy or material enters or leaves the system, ideally following the conservation of energy principle.