Which of the following best defines an ecosystem?

• A. A group of individuals of the same species living in the same area.
• B. A community of organisms interacting with each other and with their physical environment.
• C. A collection of populations of different species that live in the same area.
• D. The physical environment of a particular region, excluding living organisms.

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the term 'ecosystem.' An ecosystem is a biological system that includes all living organisms (biotic factors) in a particular area, as well as the non-living components (abiotic factors) such as air, water, and soil, with which they interact.
2. Step 2: Analyze the options provided in the question. Each option describes a different aspect of biological organization or environmental interaction. Compare these descriptions to the definition of an ecosystem.
3. Step 3: Option 1 ('A group of individuals of the same species living in the same area') refers to a population, not an ecosystem. A population is a single species in a specific area.
4. Step 4: Option 3 ('A collection of populations of different species that live in the same area') describes a community, which is a subset of an ecosystem but does not include abiotic factors.
5. Step 5: Option 4 ('The physical environment of a particular region, excluding living organisms') refers only to abiotic factors and excludes biotic factors, which are essential to defining an ecosystem. The correct answer is Option 2 ('A community of organisms interacting with each other and with their physical environment'), as it includes both biotic and abiotic components and their interactions.