Ea called on Marduk, a great warrior god, saying that if Marduk should be victorious, he would be the lord of all the gods. A great battle ensued, with gods raging against each other. Marduk reached Tiamat, the embodiment of chaos, and smashed her head with his great club. He sliced her in half, making the North Wind bear her pieces away. From each half of her ribs he created the vault of the heavens and the earth. Her weeping eyes became sacred rivers, and Tiamat was no more. —"Enuma Elish,"
Early Babylonian myth

What is the purpose of this passage from the myth?

to explain how the first humans came to exist on Earth
to explain how the heavens, earth, and rivers were created
to explain how humans should act toward one another