Concept:An ecosystem includes all living organisms and their physical surroundings, interacting together. Its main components are biotic (living) and abiotic (non-living) factors.
Explanation:Biotic components include producers (plants), consumers (animals), and decomposers (bacteria, fungi).
Abiotic components include non-living things like soil, water, air, sunlight, and minerals.
Thus, the ecosystem is made of both biotic and abiotic substances.
Options A, B, and C list only living or partial parts, but the full ecosystem requires both living and non-living.
Answer:D. Biotic and abiotic substance
