Here's why:

* Ecosystem: An ecosystem encompasses all the living organisms (biotic factors) within a specific area and their interactions with the nonliving components (abiotic factors) of their environment. This includes things like soil, water, sunlight, and temperature.

Let's look at why the other options are incorrect:

* Community: A community only includes the living organisms (biotic factors) within a specific area, focusing on the interactions between different species.

* Population: A population is a group of individuals of the same species living in a particular area, focusing only on the living organisms.

* Biosphere: The biosphere is the sum of all ecosystems on Earth. While it encompasses living and nonliving components, it's a larger scale than what the question is asking.

Therefore, the best answer is ecosystem as it specifically includes both living and nonliving components within a defined area.