An ecosystem is the community of the living + environment: forest, pond, city. The food chain: plants (producers) → herbivores → predators → decomposers (fungi, bacteria) return nutrients to soil. Remove one link — the chain breaks: no bees, no fruit. The balance holds for centuries — and is fragile.

• ●Producers: plants make food from light (photosynthesis)
• ●Consumers: eat others — herbivores and predators
• ●Decomposers: break down and return — without them the world piles up