Which of the following best explains why decomposers in soils and water are important to ecosystems?

• A. They compete with herbivores for plant resources.
• B. They break down dead organic matter, recycling nutrients back into the ecosystem.
• C. They prevent the accumulation of oxygen in aquatic environments.
• D. They produce energy through photosynthesis for primary consumers.

Answer: (B)

Verified step by step guidance

1. Understand the role of decomposers in ecosystems: Decomposers, such as bacteria and fungi, are organisms that break down dead organic matter (e.g., dead plants, animals, and waste products). This process is essential for nutrient cycling in ecosystems.
2. Identify the key function of decomposers: Decomposers break down complex organic molecules into simpler inorganic molecules, such as carbon dioxide, water, and mineral nutrients (e.g., nitrogen, phosphorus). These nutrients are then made available for uptake by plants and other primary producers.
3. Eliminate incorrect options: Decomposers do not compete with herbivores for plant resources, as they primarily consume dead organic matter. They also do not produce energy through photosynthesis, as they are not photosynthetic organisms. Additionally, decomposers do not prevent the accumulation of oxygen in aquatic environments; instead, they may consume oxygen during the decomposition process.
4. Focus on the correct explanation: The primary importance of decomposers is their role in recycling nutrients back into the ecosystem. This ensures the continuous availability of essential nutrients for primary producers, which supports the entire food web.
5. Conclude with the correct answer: The best explanation is that decomposers break down dead organic matter, recycling nutrients back into the ecosystem, which is critical for maintaining ecosystem health and sustainability.