The Himalayan Mountains

Correct answer: A. Himalayan regional sections are identified by the rivers between which they extend. The Punjab Himalaya lies between the Indus and Satluj rivers. Farther east, the Kumaon Himalaya lies between Satluj and Kali, the Nepal Himalaya between Kali and Teesta, and the Assam Himalaya between Teesta and Dihang. Therefore, placing Assam Himalaya between Indus and Satluj confuses the western Punjab section with the eastern Assam section. Option A gives the exact correction. Option B repeats the incorrect claim, so it cannot be the criticism. Option C is false because Assam Himalaya is a mountain region, not a sea island. Option D is false because the Thar is a desert region and is unrelated to the identity of Assam Himalaya. Always check both boundary rivers and their west-to-east order. Memory cue: Indus–Satluj = Punjab; Teesta–Dihang = Assam.

Correct answer: B, Kumaon Himalaya. In the west-to-east regional division of the Himalayas, river pairs mark the approximate limits of different sections. The Punjab Himalaya is between the Indus and Satluj. Immediately east of it, the Kumaon Himalaya extends between the Satluj and Kali rivers. The Nepal Himalaya follows between Kali and Teesta, while the Assam Himalaya lies between Teesta and Dihang. Thus Satluj–Kali is the identifying pair for Kumaon Himalaya. Option A is incorrect because Teesta–Dihang identifies Assam Himalaya. Option C is incorrect because Kali–Teesta identifies Nepal Himalaya. Option D, Purvanchal, refers to the eastern hills beyond the Dihang bend and is not the section between Satluj and Kali. The safest exam method is to memorize the river sequence from west to east and match the pair, rather than guessing from the name.

Correct answer: A. Dehra Dun, or Dehradun, is a well-known example of a Dun valley. Duns are longitudinal valleys associated with the Lesser or Middle Himalaya and the Outer Himalaya. They occur between the Himachal range, also called the Lesser Himalaya, and the Shiwalik range, also called the Outer Himalaya. This makes option A correct. Option B is wrong because Dehra Dun is a valley, not a peak of Himadri, the Great Himalaya. Option C is wrong because Purvanchal refers to the eastern hills and is not the defining fact about Dehra Dun. Option D is wrong because the Indus–Satluj pair identifies the Punjab Himalaya regional section, not a Dun valley. The key association is location: Dun valley = between Himachal and Shiwalik. Memory cue: “Dehra Dun lies between the middle and outer Himalaya.”