Which of the following best describes decomposers?

Decomposers play a crucial role in the ecosystem by breaking down dead organic matter, such as fallen leaves, dead animals, and waste produced by living organisms. This process of decomposition is essential for recycling nutrients back into the soil, which helps maintain soil health and supports the growth of plants. Decomposers, which include fungi, bacteria, and other microorganisms, convert complex organic substances into simpler compounds. This not only helps in nutrient cycling but also facilitates the breakdown of materials, making them available for uptake by plants.

The other choices describe different groups of organisms within the ecosystem. Organisms that photosynthesize, such as plants and algae, convert sunlight into energy but do not break down dead matter. Primary consumers are herbivores that eat plants, and organisms that produce energy from sunlight, as mentioned, refer to autotrophs, primarily plants. Thus, the definition of decomposers as organisms that break down dead matter is key to understanding their function and importance in ecological systems.