What describes the integrated system of organisms and their physical environment in a given area?

• A. Ecosystem
• B. Population
• C. Biome
• D. Habitat

Answer: (A)

An ecosystem is the integrated system of living organisms and their physical environment in a given area. It includes both the living components (plants, animals, microbes) and the nonliving surroundings (air, water, soil, climate) and the interactions among them, such as energy flow through food webs and nutrient cycling. This concept captures how organisms and their environment function together as a whole, with boundaries that can be defined by area or ecosystem processes.

A population refers to individuals of a single species in a location, not the broader web of interactions. A habitat is the specific place where an organism lives, but it doesn’t by itself describe the full network of relationships and energy/nutrient exchanges. A biome is a large-scale region characterized by climate and dominant vegetation, which is broader than a single area’s integrated system.