Who is credited with the idea of stacking increasingly smaller mastabas to create a monumental symbol of the king, s everlasting power?

Imhotep

Explanation:

Imhotep was the one originally credited with the idea to create such a monument to a king. Imhotep was an Egyptian chancellor who is believed to have been the architect of the Djoser's step pyramid. Step pyramids were the earliest type of Egyptian pyramid, and this one in particular was meant to be a tomb for the pharaoh, Djoser. It was composed of six increasingly smaller mastabas, one on top of another.

answer; taking up arms to defend the nation;

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)