The correct option is "1 only" because the Aral Sea has experienced one of the most dramatic shrinkages in history due to human activities, particularly the diversion of rivers for agricultural irrigation. This ecological disaster emphasizes the consequences of unsustainable resource management and highlights the importance of integrated water resource planning. In contrast, the Black Sea and Lake Baikal have not undergone such severe reductions in size, making the Aral Sea a critical case study for understanding human impacts on freshwater ecosystems.