In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to provide one question which clarifies the input question and it has one unique answer, and also provide an answer to the generated question. Generated question and answer should be separated with a new line.

Which civilizations developed in the fertile valley between the tigris and euphrates rivers?
What type of civilization developed in the fertile valley between the tigris and Euphrates rivers? 
 River Valley Civilization