Defining an Ecosystem

An ecosystem is a fundamental concept in environmental science. It describes a community of living organisms interacting with their non-living physical environment.

Ecosystem Components

The key components that define an ecosystem are:

• Biotic factors: These are all the living or once-living parts of the ecosystem, such as plants, animals, fungi, and bacteria.
• Abiotic factors: These are the non-living physical and chemical elements, including sunlight, temperature, water, soil, air, and minerals.

Therefore, an ecosystem fundamentally consists of both living organisms (biotic factors) and the physical factors (abiotic factors) they interact with.

Analysis of Options

Let's analyze why the correct option is the best fit:

• Option 1 (Only living organisms) is incomplete as it excludes the crucial non-living components.
• Option 2 (Living organisms and physical factors) accurately includes both biotic and abiotic elements, matching the definition of an ecosystem.
• Option 3 (Only insects) is too specific, representing only a small part of the living organisms within an ecosystem.
• Option 4 (Only physical factors) is incomplete as it excludes all living components.

The correct definition encompasses the interaction between the biological community and its physical surroundings.