In ecology, which term describes a complete interconnected system consisting of organisms and their physical surroundings?

• A. Producer
• B. Ecosystem
• C. Decomposer
• D. System

Answer: (D)

Understanding how ecologists describe the whole network of living things and their environment is tested here. The term that names that complete, interconnected web is ecosystem. An ecosystem includes all the organisms — producers that capture energy, consumers that rely on others for energy, and decomposers that recycle nutrients — along with the nonliving surroundings like air, water, minerals, and climate. Energy moves through the system and matter cycles within it, tying everything together. A more general word like system is too broad and doesn't specify the living–nonliving interactions and processes that define ecological communities. Producers and decomposers are important parts of an ecosystem, but they describe roles within the system rather than the whole together. So the ecosystem best describes this full, integrated network.