Which statement best describes the difference between primary and secondary succession?

• A. Primary begins on bare surfaces with soil present; Secondary begins on surfaces with no soil
• B. Primary begins on surfaces with no prior plant growth; Secondary follows a disruption with soil remaining
• C. Primary involves only aquatic systems; Secondary only terrestrial
• D. Primary and Secondary are the same

Answer: (B)

The key idea is that the starting conditions differ based on whether soil and an existing community are present. Primary succession starts on surfaces with no prior plant growth and essentially no soil; pioneer organisms like lichens and mosses colonize the bare substrate and gradually create soil so other plants can establish. Secondary succession occurs after a disturbance but leaves soil (and often some seeds, roots, or remaining organisms) intact, so plant communities can rebound more quickly from that existing base. This is why the statement describing primary as beginning on surfaces with no prior plant growth and secondary as following a disruption with soil remaining is the best fit. The other options misstate the role of soil, wrongly confine primary or secondary to certain environments, or claim they’re the same.