1. Which is Longest national highway of India ?

Answer: NH-7 ( Varanasi to Kanyakumari - 2,369 km)

2. Which is largest Delta of India ?

Answer: Sundarban (W. Bengal)

3. Which is highest dam in world ?

Answer:

Jinping-I Dam - 305 m (1,001 ft) in China on Yalong river.
Second Highest is Nurek Dam 300 m (980 ft) Tajikistan on Vakhsh river.

4. Which is the highest dam in India ?

Answer: Tehri Dam on Bhagirathi River in Uttarakhand (Height of 260 metres)

5. Which is the largest Zoo in the World ?

Answer: Berlin Zoological Garden (Germany)

6. Which is the longest River in the World ?

Answer: Nile

7. Which is the largest desert in India ?

Answer: Thar (Rajasthan)