The Nile River was of prime importance in the early civilization of the:

Sumerians

Inca Indians

Egyptians

Americans

Egyptian

Explanation:

The Egyptian or the Nile Valley civilization developed, as the name suggests, along the banks of the river Nile in Egypt. Its long, narrow flood plain was a magnet for life, attracting people, animals and plants to its banks, and providing ideal conditions for the development of stable communities.