Final answer:
The ancient river valley civilization of Sumer did not include pyramids as monumental structures.
Step-by-step explanation:
The statement that does not describe the ancient river valley civilization of Sumer is d) Pyramids as monumental structures. While Sumerian civilization developed advanced irrigation systems, a cuneiform writing system, and had polytheistic religious beliefs, they did not construct pyramids as monumental structures like the ancient Egyptians did.