I'm not sure what the choices are, but here are some answers that are true about ecosystems:
An ecosystem is a large community of living organisms
Each ecosystem has its own community.
Once defined, an ecosystem is a unit scientists can analyze
The living parts (plants, animals and microbes) of an ecosystem are the biotic components.
The greater the inputs, the greater the biodiversity in an ecosystem.
Ecosystems are dynamic and a greater input leads to a greater biodiversity.
