Correct Option
The correct option is (c) 2 and 3 only.
Explanation
The Ganga-Brahmaputra Basin encompasses a diverse range of topography, extending from the steep slopes of the Himalayas to the flat plains and the marshy delta regions. This variation in altitude, climate, and landforms results in a distinct stratification of natural vegetation across the basin.
Statement-wise Analysis
- Statement 1 is Incorrect: Uttarakhand and Sikkim are located in the Himalayan region, characterized by high altitudes and cool climates. Coniferous trees, such as Pine, Deodar, and Fir, thrive in these conditions. They are not absent; rather, they are a dominant feature of the vegetation in these states due to the cold climate and steep slopes.
- Statement 2 is Correct: The type of vegetation is strictly dependent on the landforms and climatic conditions. In the basin, the vegetation transitions from coniferous forests in the mountainous regions to tropical deciduous forests in the plains and mangrove forests in the deltaic regions.
- Statement 3 is Correct: The delta area formed by the Ganga and Brahmaputra rivers is covered with mangrove forests. This region is famously known as the Sundarbans, named after the Sundari trees which are a characteristic species of these tidal forests.
Key Takeaway: Vegetation in the Ganga-Brahmaputra basin follows an altitudinal and topographical gradient: Coniferous forests in the cool Himalayas, Deciduous forests in the plains, and Mangrove forests in the delta.