Which of the following was an achievement of the Harappan Civilization, the earliest known group in the Indus Valley?

A.

indoor drainage

B.

refrigeration

C.

windmills

D.

the elevator

For its indoor drain

the dynastic cycle is just a cycle showing how empires rise and fall and the Mandate of heaven is what the Zhou Dynasty claimed gave them the right to rule. I guess they are related because Spring in the Dynastic Cycle is when an Empire would get the Mandate

The answer is A drain