Which of the following is an example of an ecosystem (a community of organisms interacting with each other and with the physical environment)?

• A. A rock formation with no living organisms present
• B. A single population of rabbits living in a meadow
• C. A freshwater pond containing algae, insects, fish, bacteria, water, and dissolved nutrients
• D. A DNA molecule inside the nucleus of a plant cell

Answer: (C)

Verified step by step guidance

1. Understand the definition of an ecosystem: it includes a community of living organisms interacting with each other and with their physical environment.
2. Evaluate each option to see if it contains both living organisms and non-living environmental components interacting together.
3. Option 1 (a rock formation with no living organisms) lacks living organisms, so it is not an ecosystem.
4. Option 2 (a single population of rabbits) includes living organisms but does not include the physical environment or other species, so it is a population, not an ecosystem.
5. Option 3 (a freshwater pond containing algae, insects, fish, bacteria, water, and dissolved nutrients) includes multiple species and their physical environment interacting, which fits the definition of an ecosystem.