(a) Only one
Explanation: Top 5 Dam in India
1. Tehri Dam: In the state of Uttarakhand, there is a dam called the Tehri. Its 260.5-meter height makes it India’s tallest dam. Additionally, it ranks among the 10 highest dams in the world. On the Bhagirathi River is where this Dam is located.
2. Bhakra Nangal Dam: The Bhakra Nangal Dam is a concrete gravity dam on the Sutlej River in India. It’s located on the border of Punjab and Himachal Pradesh, and is Asia’s second tallest dam at 225.55 meters (740 ft) high. The dam is also the world’s highest straight gravity dam, and is 518 meters long. The Indian Army constructed the dam, which opened to the public in 1975.
3. Hirakud Dam: The Hirakud Dam is situated in the Orissa state. With a total length of 25.79 km, it is the longest dam in India. Additionally, it is among the top ten longest dams in the world. On the River Mahanadi is where the Hirakud Dam is located.
4. Nagarjuna Sagar Dam: The Telangana state is home to the Nagarjuna Sagar Dam. It is the largest masonry dam ever constructed in India. It is the world’s largest lake created artificially. It is 1.55 kilometres long and features 26 gates. It is located along the Krishna River. (A masonry dam is a dam made from stone, brick, rubble, or concrete blocks, sometimes joined with mortar. They can be either gravity or arch-gravity type.)
5. Sardar Sarovar Dam: Gujarat is where the Sardar Sarovar Dam is situated. The Narmada Valley Project’s largest dam, it. The Madhya Pradesh, Rajasthan, and Maharashtra neighbouring states stand to gain from this dam. It is located by the Narmada River.

(a) 1, 2 and 3
Assam is located in the north-eastern part of India. – In the North, it is bounded by the kingdom of Bhutan and state of Arunachal Pradesh. – To the East, it is bounded by the states of Nagaland and Manipur. – To the West it is bounded by Bangladesh and states of Meghalaya and West Bengal.
West Bengal also shares its borders with three countries because of its narrow northward extension. Those countries are-Bangladesh to the East and Nepal and Bhutan in the North.
Mizoram is a landlocked state in North East India whose southern part shares 722 kilometers long international borders with Myanmar and Bangladesh, and northern part share domestic borders with Manipur, Assam and Tripura.

(b) Only two
In India, exploration and study of geothermal fields started in 1970. (Statement 1 is incorrect)
Geological Survey of India has found around 350 geothermal energy locations in the country. The most promising of these is in the Puga valley of Ladakh.
India has 7 geothermal provinces [viz. Himalayas, Sohana, West Coast, Cambay (Gujarat), Godavari, Mahanadi and Son-Narmada-Tapi (SONATA)] and a number of geothermal springs. (Statement 2 is correct)
Geothermal resources in India have been mapped by GSI and a broad estimate suggests that there could be 10 gigawatts (GW) geothermal power potential, as per the Ministry of New and Renewable Energy (MNRE).
In 2013, the Chhattisgarh government has decided to establish the Geothermal Power Plant in the country at Tattapani in the Balrampur district.
In 2021, an agreement was signed to establishing the first geothermal Power Project in Ladakh.
Satellites like the IRS-1 have played an important role, through infrared photographs, in locating geothermal areas.
Government Initiatives
For Industrial Projects, the government has planned to provide a capital subsidy of up to 30%.
First Geothermal power plant to come in Chhattisgarh by joint cooperation of NTPC and Chhattisgarh Renewable Energy Development Agency (CREDA). Tattapani geothermal field in SONATA geothermal province. (Statement 3 is correct)
Ministry of New and Renewable Energy (MNRE) provides large incentives and subsidies for Research, Design, Development and Demonstration (RDD&D) for harnessing geothermal energy in India.
Ministry of renewable energy has planned to generate geothermal energy up to 1000 MW by 2022. (Statement 4 is incorrect)

(a) Only one pair
In January 2024, five new sites were added to the list of Ramsar Sites in India.
1. Ankasamudra Bird Conservation Reserve – Karnataka
2. Aghanashini Estuary – Karnataka
3. Magadi Kere Conservation Reserve – Karnataka
4. Karaivetti Bird Sanctuary – Tamil Nadu
5. Longwood Shola Reserve Forest – Tamil Nadu
Others
Pala Wetlands – Mizoram
Khijadia Wildlife Sanctuary in Gujarat and Bakhira Wildlife Sanctuary in Uttar Pradesh were announced as Ramsar sites (Wetlands of International Importance) on the occasion of World Wetland Day 2022 (2nd February 2022) held at Sultanpur National Park, a Ramsar site in Haryana.
Haiderpur Wetland in Uttar Pradesh has been added as the 47th Ramsar Site in December 2021. It is a human-made wetland formed in 1984 and is located within the boundaries of Hastinapur Wildlife Sanctuary.

(d) All four
Nubra Valley
The Nubra Valley acts as the gateway to the strategically important Siachen Glacier and Karakoram Pass. The Karakoram Pass on the northwest side connects the valley with Xinjiang, China. (Statements 1 and 2 are correct)
The Nubra River is a river in the Nubra Valley of Ladakh in India. It is a tributary of the Shyok River (a part of the Indus River system) and originates from the Siachen Glacier.
Siachin Glacier
It is the longest glacier in the Karakoram and second-longest in the world’s non-polar areas in the world.
The area was once part of the ancient Himalayan trade path, the Silk Route that connected China to the Middle East.
Indian subcontinent in the extensively glaciated portion of the Karakoram sometimes called the “Third Pole”. (Statements 2 and 4 are correct)