Explanation:

- Option 1: Lake

- Lakes are generally natural ecosystems where various species of plants, fish, and microorganisms interact with each other in a balanced environment.

- Option 2: Garden

- Gardens are man-made environments designed for aesthetic or practical purposes like growing vegetables.

- Correct Answer.

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- Option 3: Pond

- Ponds can be natural but are often artificially created for specific purposes like aquaculture or recreation.

- Option 4: Forest

- Forests are natural ecosystems with diverse flora and fauna coexisting in a complex, interconnected way.

Gardens are the most typical example of an artificial ecosystem.