Answer:
Tigris River
Step-by-step explanation:
The river that is shown on this map is the Tigris River. This river has been one of the two, together with Euphrates, gave the basis for the development of the earliest civilization, the Sumerians. This River runs roughly parallel with Euphrates, creating a very fertile valley between them i the middle of the desert. These two rivers merge in the lower flow, and shortly after they merge into one they enter the Persian Gulf.