In Environment and Ecology, which term combines the facts “energy flows while nutrients cycle through the system” and “a functional unit of organisms and their physical environment”?

Correct Answer: Option A — Ecosystem. Ecosystem is correct because it is a functional unit of organisms and their physical environment. Ecosystem is also specifically associated with energy flows while nutrients cycle through the system. Two additional identifying facts are that Ecosystem is energy flows while nutrients cycle through the system and Ecosystem is associated with a pond, forest or grassland can be studied as an ecosystem. Why the other options are incorrect: • Option B — Food Chain: Food Chain is a linear sequence showing transfer of food energy. • Option C — Biodiversity Hotspot: Biodiversity Hotspot is a region combining exceptional endemism with severe habitat loss. It is incorrect here because its separate identifying association is parts of the Himalaya and Western Ghats-Sri Lanka hotspots occur in India. • Option D — Wetland: Wetland is land where water controls ecological conditions for significant periods. It is incorrect here because its separate identifying association is wetlands can store floodwater and support specialized biodiversity. Exam Takeaway: Connect Ecosystem with “a functional unit of organisms and their physical environment” and “energy flows while nutrients cycle through the system”.