- A plant requires nutrients for survival
- Soil provides nutrients for plants
- So, plants require nutrients in soil for survival

- Plants require nutrients in soil for survival
- If something requires something else then that something else is important to that something
- So, nutrients in soil are important to plants

- Nutrients in soil are important to plants
- Plants are a part of an ecosystem
- So, nutrients in soil are important for an ecosystem

- Decomposition is when a decomposer recycles / returns nutrients / nitrogen from dead organisms to the soil by eating those dead organisms
- Decomposition is when a decomposer breaks down dead organisms
- Hence, a decomposer breaks down dead organisms to return nutrients to soil

- Nutrients in soil are important for an ecosystem
- A decomposer breaks down dead organisms to return nutrients to soil
- Hence, decomposers breaking down dead organisms to return nutrients to soil is important for an ecosystem

So, decomposers breaking down dead organisms to return nutrients to soil is important for an ecosystem
Question
An ecosystem is a community of organisms interacting with their physical environment. Why are decomposers an important part of ecosystems?

Context
- A plant requires nutrients for survival 
- If something requires something else then that something else is important to that something 
- Plants are a part of an ecosystem 
- Decomposition is when a decomposer recycles / returns nutrients / nitrogen from dead organisms to the soil by eating those dead organisms 
- Decomposition is when a decomposer breaks down dead organisms 
- Soil provides nutrients for plants