Here's why:
* Ecosystem: This is a community of interacting organisms (biotic factors) and their physical environment (abiotic factors) working together as a functional unit. This level encompasses both living things and their surrounding nonliving components, making it the smallest unit that exhibits this interaction.
Let's look at other options and why they aren't the answer:
* Biosphere: This is the entire portion of Earth inhabited by life, encompassing all ecosystems. It's too large of a scale.
* Community: This is a group of interacting populations of different species within a defined area. It focuses on living organisms only.
* Population: This is a group of individuals of the same species living in the same area. It again focuses only on living organisms.
* Organism: This is a single living individual, and it doesn't encompass the nonliving components of the environment.
Therefore, the ecosystem is the fundamental level of organization that incorporates both living and nonliving factors.
