4. Why do you think some of the first complex civilizations (Sumerian, Akkadian, Babylonian and Egyptian) formed in the area known as the fertile crescent? A valid reason some of the first complex civilizations formed in Fertile Crescent is the fertile soil in Mesopotamia. Also, because of the expansion of irrigation, the civilizations grew when the farming and agriculture blossomed. To explain, the Fertile Crescent was an excellent place to settle down because they would not have to worry about not having food since the soil was fertile. Lastly, it also had water bodies to fish in, other animals around to hunt, and berries to gather.