韓文（韓語）題庫下載題庫

        One key to the stability of natural systems is the diversity of plants, insects, and animals that live in them. If nature is left undisturbed by humans, it naturally evolves ecosystems with incredible diversity, leading to many inter-connected negative feedback loops that suppress disruptive changes. Recent research shows that diverse plant ecosystems are not only more resilient and robust, they’re also more productive and consume more CO₂. On the other hand, when humans manage an ecosystem to maximize output, they typically create a monoculture  just one crop with as few weeds and insects as possible. In the short run, a simplified ecosystem gives humans rich returns of that one crop. But it’s also very vulnerable. Because any single crop falls easily to unexpected loss, farmers should plant diverse crops and rotate them on their fields. The researchers studying productivity from biodiversity have found that polycultures of about ten species produced the greatest bioproduct.