What cultural description is often used to describe the earliest civilizations in this region (mesopotamia)?
a) the indus valley
b) the phoenician belt
c) the fertile crescent
d) the muslim heartland

The correct answer is C. The cultural description used to described the earliest civilizations in Mesopotamia is the Fertile Crescent.

Explanation:

The Fertile Crescent is a term for an ancient fertile area north and east of the Arabian Desert and Mesopotamia and along the Mediterranean in the Middle East.  

The area was probably more fertile in ancient times than it is today. Often the entire fertile Middle East, including the river valleys of Mesopotamia and the lower reaches of the Nile, is meant by the fertile crescent. But early agriculture associated with the term originated in the forested mountain slopes of the border zone of this area - in Israel, Lebanon, Syria, Turkey, northern Iraq and northwestern Iran.   Here agriculture originated on a larger scale, probably the first place in the world, sometime between 9,600 and 8,500 BC; this situation prompted the foundation of the first city-organized settlements in mankind such as Babylon.