Primary succession occurs on surfaces where no soil exists.

• A. Succession That Occurs On Surfaces Where Soil Exists
• B. Secondary Succession In Mature Forests
• C. Succession That Occurs On Surfaces Where No Soil Exists
• D. The Gradual Replacement Of One Species By Another

Answer: (C)

Primary succession begins on surfaces with no soil. When bare rock or new land is exposed, there’s no soil to support most plants, so pioneer organisms that can live directly on rock—like lichens and mosses—colonize first. These pioneers slowly break down the rock and accumulate organic matter from their own remains, creating a thin layer of soil. As soil develops, more plants can establish, leading to a gradual, long-term change in the community toward a more complex ecosystem. This differs from secondary succession, which happens after a disturbance in an area that already has soil. The idea of succession as a gradual replacement of one species by another is true in general, but it doesn’t specify the lack of soil that defines primary succession.