Explanation: Rajasthan, a state in northwestern India, is known for its diverse topography, which includes the vast Thar Desert and the Aravali Range. The Aravali Range is a significant mountain range that runs through Rajasthan, extending from the southwest to the northeast of the state. It is one of the oldest mountain ranges in the world, formed over 1.8 billion years ago.
The Aravali Range plays a crucial role in the geography of Rajasthan. It acts as a natural barrier, separating the arid and semi-arid regions of the Thar Desert in the west from the more fertile and green regions in the east. The range influences the climate of the state, with the western side being drier and more arid due to the rain shadow effect, while the eastern side receives more rainfall.
The Aravali Range is not only a geographical feature but also a significant ecological and cultural landmark. It is home to various flora and fauna, including several endemic species. The range also has historical and cultural significance, with many temples and pilgrimage sites located along its length.
In contrast, the term "Northern Mountains" is not specific to Rajasthan's geography. Rajasthan does not have a distinct mountain range referred to as the "Northern Mountains." The Aravali Range is the primary mountain range in Rajasthan, and it is not located in the northern part of the state.
Therefore, the correct answer is the Aravali Range, as it is the significant hill range that separates the Thar Desert from the rest of Rajasthan. The Aravali Range is a crucial geographical feature that influences the state's climate, soil, and biodiversity, making it an essential part of Rajasthan's topography.