The answer is:
A. Ziggurats were built on high platforms to keep them safe from floods.
and C. Much of life in Sumerian cities centered on the ziggurat.
Explanation:
In Mesopotamia, there were sometimes floods. Ziggurats had to protected from this so they were built on high platforms.
Ziggurats were important temples and were very important to the people. So much of life in Sumerian cities centered on the ziggurat.
