because bad things can be added to the ecosystem and there will be less oxygen which then kills the plants and animals in that ecosystem since they wont be able to survive
Mineral cycle
plants take minerals out of the soil and air to build macro molecules
they are passed through food chains to animals
complex cycles have evolved that recycle the chemicals needed for life
Nitrogen cycle
nitrates in the soil are absorbed by plant roots and used to build plant proteins
then eaten by animals and stored as animal proteins
dead plants and animals are broken down and nitrate is returned back into the soil
