What type of organism is a 'decomposer'?

A decomposer is an organism that breaks down dead organic material, returning essential nutrients to the ecosystem. This process is critical for nutrient cycling and helps maintain the health of ecosystems by ensuring that organic matter is recycled. Decomposers, which include fungi, bacteria, and certain insects, play a vital role in breaking down complex organic substances into simpler compounds that can be reabsorbed by plants and other organisms. By facilitating this breakdown process, decomposers help sustain life and promote ecosystem balance.

The other options involve organisms that serve different functions within an ecosystem. Producers generate energy through processes like photosynthesis, which is vital for food chains. Organisms that perform photosynthesis convert light energy into chemical energy, while those that compete for resources include various species vying for limited supplies such as food or habitat but do not directly engage in the decomposition process. Thus, the role of a decomposer is unique and essential for recycling nutrients and maintaining ecological equilibrium.