They help to enrich the soil when they die. The decomposers will break down their dead body into simpler substances, then the substance(can also be called nutrients) will be returned back to the soil as 'fertilisers' to help the plant in healthy growth.
The animal effect is ecosytem is not pollutied and the human is
probly probly not
Acid rain affect the ecosystem by reforming the way the animals live.This can happen by the cars and factory's fumes. And it can EFFECT by hurting things
Because they eat dead animals
There is fish, cows, chickens, goats. etc.
Because it eats other animals in it and if there is no animals they won't be able to do there roll
Because plants absorb nutrients from the plants and animals.
it is because it causes animals to eat plants and we lose plants
People affect Ecosystems by catching/ hunting the animals, in that reason the animals start to disappear and, let say we caught a sea urchin, then they start to disappear, and the animals like otters that eat sea urchins start to disappear because they are starving.
it can affect an ecosystem by killing it or burning it
the factor that affect and change the ecosystem is how the people living
If their are more plants then it will be no space for the other plants and animals