Define an ecosystem.

An ecosystem is best defined as a community of living organisms and their interactions with the abiotic environment. This definition highlights the dynamic relationships between the biotic factors, such as plants, animals, and microorganisms, and the abiotic factors, including water, soil, temperature, and nutrients.

In an ecosystem, these components work together to form a complex web of interactions that sustain life. Each organism plays a specific role, contributing to the balance and health of the system. For example, plants (producers) convert sunlight into energy through photosynthesis, which supports herbivores (primary consumers), and subsequently larger predators (secondary or tertiary consumers) that rely on those herbivores for food. Additionally, decomposers break down dead organic matter, returning nutrients to the soil and completing the cycle of matter within the ecosystem.

In contrast, the other definitions provided do not encompass the full essence of what an ecosystem is. A large geographical area with similar climate refers more to biomes rather than the intricate interactions present in an ecosystem. The notion of a group of different species living without interaction undermines the interdependence that characterizes ecosystems. Finally, a diverse population of a single species would miss the integral part of inter-species relationships that are vital