The correct answer is 4) huge structures that served as temples.
What was NOT a feature of ancient Indus cities was "huge structures that served as temples."
What truly were features of ancient Indus cities were city blocks laid out in a grid pattern, a standardized system of weights and measure, a sanitation system, and a large, central building that stored grain.
Historians agree that the Indus Valley civilization developed approximately 5,500 years ago. It was one of the first civilizations on earth, with others such as the Sumerians and the Egyptians. The Indus Valley established in modern-day India and Pakistan.
