Explanation:

The different racial groups are:
1. The Negritos: Negrito features are met with particularly amongst the Andaman islanders and most probably the Uralis Nilgiri hills, Kadors of Kochi, Pullayans of Palni hills, etc. Besides some tribes like the Angami Nagas in
the north-east and the Badgis in the Rajmahal hills in Jharkhand etc. possessing some physical traits reminiscent of the Negrito are seen. The Negrito race is characterised by short stature, dark chocolate brown skin, wooly hair, bulbous forehead, broad flat nose and slightly protruding jaws.
2. The Proto-Australoids: They constitute the bulk of population in many isolated and semi-isolated parts of central land southern India. The Veddahs, Malavedahs, Irulas and Sholagas are the true representatives of Proto- Australoids. The Bhils, Kols, Badagas, Korwas, Kharwars, Mundas, Bhumjis and Malpaharis of the highlands of Central India and the Chenchus, Kurumbas, Malayans and Yeruvas of South India may all be treated as Proto- Australoids.
3. Mongoloid: The tribes of Garo, Khasi, Jaintia, Lepchas, Chakmas, Murnis, Naga and Daffla etc. belong to the Mongloid race.
4. Nordics: The main concentration of these people is in the north-western part of the country. They are a predominat type in Punjab, Har yana and Rajasthan. They are mostly represented among the upper castes of
North India particularly in Punjab.