Answer:
A lot...
Explanation:
Having abundant species in an ecosystem (plant or animal) the benefit one another is called biodiversity. Biodiversity can consist of the mere food chain, to complex symbiotic relationships among creatures. If an ecosystem were to have no species, there would be no balance between a self-sustaining ecosystem. Any naturally found ecosystem will have biodiversity, otherwise that ecosystem will break (usually it's brand new, crashing ecosystems have to have even one factor removed to do so. Therefore, why would this said 'ecosystem' even begin?).
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