Which of the following best describes an ecosystem?

• A. A collection of cellular structures within a single organism
• B. A community of living organisms interacting with their environment
• C. An individual organism's genetic makeup
• D. A system of organelles within a cell

Answer: (B)

An ecosystem is best described as a community of living organisms interacting with their environment. This definition encapsulates the dynamic relationships among various species—including plants, animals, fungi, and microorganisms—and the non-living components of their environment, such as water, soil, and climate. In an ecosystem, these interactions can include predator-prey relationships, symbiosis, competition for resources, and responses to environmental changes.

The essence of an ecosystem lies in these biotic (living) and abiotic (non-living) components working together to sustain life. This interaction allows for energy flow through food webs and nutrient cycling, which are fundamental processes in maintaining ecological balance. By understanding ecosystems in this way, one can appreciate the complexity and interconnectedness of life on Earth.