Concept:Accelerated soil erosion is caused by human activities that remove vegetation cover and expose soil.Explanation:Intensive cultivation repeatedly disturbs and exposes the soil, making it easy to wash or blow away.Overgrazing removes grass cover and compacts the soil, increasing surface runoff and erosion.Other options like mulching and cover crops are soil conservation methods, not causes of erosion.Therefore, the correct combination is intensive cultivation and overgrazing.Answer:D. intensive cultivation and overgrazing