Question

Ecosystems are characterized by:

Options

• One-way flow of energy through the biotic community of an ecosystem.

• Interactions of organisms among themselves and the physical and chemical environment.

• Cycling of materials from the abiotic environment through the biotic community and back to the abiotic environment.

• All of the above.

Answer 1

All of the above.

Explanation:

Ecosystems show one‑way energy flow: sunlight fixed by producers and lost as heat through trophic levels; also interactions among organisms and with abiotic factors that structure communities; and cycling of nutrients between biotic and abiotic pools. These three together define ecosystems.