Final answer:
The essential truth of the story of the Great Flood is that it is a common theme found in various ancient cultures and religions, depicting a divine punishment for humankind's sins and the survival of a chosen few.
Step-by-step explanation:
The essential truth of the story of the Great Flood is that it is a common theme found in various ancient cultures and religions, including the Hebrew Bible, Mesopotamian legends, Ancient Egyptian mythology, and Sumerian stories. Although the specific details and motivations differ across these traditions, the flood is generally depicted as a divine punishment for the sins of humankind. The story often emphasizes the survival of a chosen few who escape the flood and the potential for redemption or salvation.