Which one of the following is the youngest mountain range of India?

Himadri is the answer because age is the test here, and the Himalayas are India's youngest mountain system. They are young fold mountains, formed in the Tertiary period, roughly 50 million years ago, when the Indian plate collided with the Eurasian plate. The Himadri, or Greater Himalaya, is the core range of that system, so it is the youngest major range in the Indian list.

• Aravalli: One of the oldest fold mountains on earth, from the Precambrian era. Its long erosion has reduced it to hills.
• Western Ghats: An old Precambrian-origin escarpment, shaped by Gondwana break-up and later uplift. It is not a young fold range.
• Vindhya: A Proterozoic range made of the Vindhyan sediments. It is much older than the Himalayas.

Mains link: the youth of the Himalayas explains their steep slopes, frequent landslides and high seismicity, which is a GS1 geomorphology and GS3 disaster-management point.

Trap: Confusing the youngest range with the highest or most prominent one. Also note that the Siwaliks are the youngest outer range within the Himalayan system, but they are not among the options here.