The sumerian calendar was based on a. the flooding of rivers. c. the movement of the sun. b. the movement of the moon. d. 365 days.

The correct answer would be D) 365 days and this was based on the whole 12 moon phases = 12 months so you could say the moon is big cause of this making of the calendar. Below is a image of the calendar, i take no credit for it i just found it off google.

Idont understand the question