Final answer:
The Epic of Gilgamesh was written entirely in cuneiform script, one of the earliest forms of writing used by the ancient Mesopotamians.
Step-by-step explanation:
The Epic of Gilgamesh was written entirely in cuneiform script, which is one of the earliest forms of writing. Cuneiform was used by the ancient Mesopotamians, and it consisted of wedge-shaped marks made on clay tablets. These clay tablets would then be baked to preserve the writing.