Which river is completely within the muslim lands of 661

Tigris River is completely within the Muslim lands of 661

Explanation:  

This civilization is located on the east of Mediterranean Sea. The Tigris River with its tributaries form a river system in western Asia. From the sources in the Taurus Mountains of eastern turkey they flow through Syria through Iraq into the Persian Gulf. The flow of the water is from the Southeaster mountains of Turkey. Transcript of the Tigris River was very important for ancient civilization.

answer; oxygen to the brain;