NSF Senior Science Bee Practice Exam

Decomposers play a crucial role in ecosystems by breaking down dead organic matter, such as fallen leaves, dead animals, and waste products, and recycling nutrients back into the soil. This process is essential for maintaining the health and balance of ecosystems, as it allows nutrients to be reused by primary producers, such as plants, which are the foundation of the food web. Without decomposers, dead matter would accumulate, and essential nutrients would be lost from the ecosystem, leading to reduced soil fertility and disrupted ecological balance.

The other options, while they describe important processes or roles within an ecosystem, do not accurately characterize the function of decomposers. For instance, the production of energy through photosynthesis is primarily the role of autotrophs (like plants), while the consumption of primary producers is a function of herbivores. Competing with herbivores for resources is not relevant to the role of decomposers, as they assist in nutrient cycling rather than competing for resources. Thus, the primary function of decomposers is to break down dead matter and recycle nutrients, making option C the appropriate answer.