Name the two headstreams of the Ganga. Where do they meet to form the Ganga?

Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?

State some economic benefits of rivers and lakes.

Below are given names of a few lakes of India. Group them under two categories natural and created by human beings.

1. Wular
2. Dal
3. Nainital
4. Bhimtal
5. Gobind Sagar
6. Loktak
7. Barapani
8. Chilika
9. Sambhar
10. Rana Pratap Sagar
11. Nizam Sagar
12. Pulicat
13. Nagarjuna Sagar
14. Hirakund