CBSE Class 6 Answered

The four reasons are

1. Staying at one place finished all available food—plant or animal resources.

2. Animals moved from place to place, and hence, this made the hunter-gatherers to move along with them for hunting them down.

3. Plants and trees bore fruit in different seasons. Thus, people had to move season to season to find different kinds of plants.

4. Plants and animals needed water to survive. Although most of the water bodies (lakes, ponds and streams) were perennial, some were seasonal. Thus, people living on the banks had to go in search of water during the dry seasons.