What type of layer transition would indicate a shift from a massive to moderated soil structure?

The transition from a massive to a moderated soil structure is best indicated by the formation of peds within the soil. Peds are naturally occurring aggregates of soil particles, and their presence signifies a development of structure that allows for improved aeration, water infiltration, and root penetration. When soil transitions to a moderated structure, it typically moves away from being dense and massive, which can hinder those processes.

In contrast, a clear distinction of soil layers might signal different soil horizons but does not necessarily imply a structural change in terms of particle aggregation. A homogeneous soil indicates uniformity in composition and texture, and direct fusion of layers without separation suggests a lack of distinction between layers, which also does not reflect the development of a moderated soil structure. Therefore, the formation of peds is essential in identifying this structural evolution in the soil, making it the correct choice in this context.