Question

explain why nomadic tribes need to move from one place to another

Answer 1

Nomads are people who do not live in one place but move from one area to another to earn their living. Their main occupation is cattle rearing for which they need availability of water and pastures for grazing their animals. When the pastures get depleted they move to another place with their animals, looking for pasture and water. When the water and pasture get depleted they move again and keep repeating the cycle.   

Advantages 
(i) The movement of the nomads allows the pasture to regrow and recover. 
(ii) It helps to protect the ecology of the environment.
(iii) It prevents the overuse of pastures. 
(iv) The cattle by the dung help in providing manure.  

Answer 2

they need to move from one place to another in the search of food and shelter
hope this helps you.