Answer:
The correct answer is "a large-scale natural system such the Great Lakes".
Explanation:
Mathematical models are used in scientific investigations to study complex systems. This applies to the study of ecosystem dynamics of large-scale natural systems such as the Great Lakes. The Great Lakes comprise five lakes that in conjunction are 244,106 km2 long, with a complex ecosystem that includes invasive species, climate change, pollution, among other factors. It will be very complicated to study the ecosystem of such a large habitat without using mathematical models.