A cell is made up of different structures
You would find layers in a sedimentary rock, because it has different types of other rock combined in it.
Answer:
The species that make up an ecosystem are connected in complex 'food webs' of eater and eaten. When one species disappears, its predators can no longer eat it and its prey are no longer eaten by it. Changes in these populations affect others. Not only that but the ecosystem would be dramatically different or cease to exist altogether.
