Why did the coastal and Plateau people separate groups?

The coastal Indians were organized into many tribes.

Explanation: The coastal Indians were organized into many tribes. Each tribe had only a few hundred members. These coastal tribes were separated from each other by dense forests, mountains, and water. The plateau tribes were much larger, but fewer in number.

what are the sentences?

the answer should be:

the intervention of the supernatural gives gilgamesh hope that he will defeat humbaba.