Question

a.
River valleys have the best soils because​

Answer 1

Answer:

River valley are said to have the best said because the soil is very fertile.

Answer 2

Explanation:

The river valleys are said to have the best soil because the soil is very fertile. In the Mesopotamia, convergence was of the Euphrates and the Tigris rivers produces the rich fertile soil and supplies the water for irrigation.

I hope this answer will help.