Which of the following best describes the role of fungi as decomposers?

Fungi play a crucial role in ecosystems as decomposers by breaking down organic matter. This process involves the secretion of enzymes that digest complex organic substances such as dead plants, animals, and other organic waste. As fungi break down this material, they are able to absorb nutrients for their own growth, but they also release essential nutrients back into the soil, which can be utilized by plants and other organisms. This nutrient cycling is vital for maintaining healthy ecosystems, as it helps to support plant growth and nutrient availability.

The other options describe functions that do not align with the primary role of fungi as decomposers. For example, converting sunlight into energy is a characteristic of photosynthetic organisms like plants and algae. Synthesizing nutrients primarily describes what plants do through photosynthesis, not fungi. While fungi do produce carbon dioxide during respiration, this is a byproduct of their metabolic processes and does not capture their essential function in breaking down organic matter. Thus, the correct answer highlights the fundamental ecological role fungi play in nutrient cycling through decomposition.