Which statement best describes the role of decomposers in nutrient cycling?

• A. They regulate population size.
• B. They convert chemical energy from glucose.
• C. They store energy in the form of starch.
• D. They break down dead matter and release nutrients.

Answer: (D)

Decomposers play a key role in nutrient cycling by breaking down dead matter and releasing nutrients back into the environment, where plants can reuse them. They convert complex organic materials from dead organisms and waste into simpler inorganic nutrients (like nitrogen and phosphorus) that become available for uptake by plants and other organisms. This recycling keeps nutrients circulating through the ecosystem and maintains soil fertility.

Other processes described are different. Regulating population size involves interactions like predation and competition, not just decomposition. Converting chemical energy from glucose happens in living cells during metabolism, not in the act of decomposing dead matter. Storing energy as starch occurs in photosynthetic or storage tissues, not in decomposers.