Which type of organism breaks down dead or decaying materials while producing carbon dioxide?

The correct choice is a decomposer. Decomposers play a crucial role in the ecosystem by breaking down dead or decaying organic matter, such as dead plants and animals. This process of decomposition is essential for recycling nutrients back into the soil, and it involves various microorganisms like bacteria and fungi. During decomposition, these organisms break down complex organic compounds, which leads to the release of carbon dioxide as a byproduct. This carbon dioxide can then be utilized by producers (like plants) during the process of photosynthesis, contributing to the carbon cycle in nature.

In contrast, consumers are organisms that feed on other living organisms; producers create their own food through photosynthesis, and scavengers feed on already dead animals but do not break down organic material at the micro-level like decomposers do. Understanding the role of decomposers highlights their importance in maintaining ecological balance and nutrient cycling.