Define an ecosystem. Give a few instances of an ecosystem.

Explanation

An ecosystem may be defined as a structural and functinal unit of the biosphere, comprising living organisms and their non-living environment that interact by means of food chains and chemical cycles resulting in energy flow, biotic diversity and material cycling to form a stable, self-supporting system.
Few instances of an ecosystem are a pond, a lake, a grassland, a desert, a village, a forest etc.