What conclusion is strengthened by the highly eroded condition of the Aravalli Range?

Correct answer: It is a very old mountain range

The direct answer is A: the Aravalli is a very old mountain range. A mountain range that has been exposed to weathering and erosion for a very long geological period gradually becomes lower, narrower and more broken. The Aravalli Range is among the ancient geological mountain systems of India and is much older than the young, high Himalayas. The reasoning is: strong erosion over immense time removes material; removal reduces height and sharpness; therefore a highly eroded range generally indicates great age, although erosion alone should not be used as the only possible geological evidence. Option A is correct because it gives the conclusion supported by the Aravalli’s worn-down appearance. Option B is wrong because the Himalayas are the young fold mountains, whereas the Aravalli is not a newly formed Himalayan chain. Option C is wrong because sea tides do not build a long inland mountain range of this kind. Option D is wrong because the Aravalli is not part of the Ganga Delta; a delta is a depositional landform made near a river mouth. The memory cue is: “Aravalli is ancient and worn; Himalaya is young and high.”