What are decomposers and why are they important?

• A. Primary producers that create energy from sunlight.
• B. Organisms like fungi and bacteria that break down dead material, returning nutrients to the ecosystem.
• C. Organisms that prevent nutrient cycling.
• D. Animals that eat plants exclusively.

Answer: (B)

Decomposers are organisms that break down dead plants and animals and their waste, returning nutrients to the environment so plants and other organisms can reuse them. This recycling keeps essential elements like carbon, nitrogen, and phosphorus available in the soil and water, which supports new plant growth and the whole food web. Fungi and bacteria are common examples because they can break down tough organic matter into simpler substances that organisms can take up.

If energy flows through an ecosystem, decomposers help close the loop by releasing nutrients that producers need to start the cycle again. Without them, dead material would pile up and nutrients would stay locked away, making it harder for life to continue thriving. The other options describe producers that make their own food from sunlight, factors that would block nutrient cycling, or animals that eat plants—the roles don’t match what decomposers do.