The smallest functional ecological unit is _?

Answer: [C] Ecosystem

An ecosystem is community plus its physical environment. Thus, ecosystem is a complex community of living plants, animals, and microorganisms (called biotic components of ecosystem) linked by energy and nutrient flows that interact together and their physical environment (called abiotic component of ecosystem) such as soil, air, water, sunlight etc. An ecosystem is the smallest functional ecological unit. An ecosystem can be natural or manmade.

This question is a part of GKToday's Integrated IAS General Studies Module