Which theory most likely led to the development of a democracy?

The theory that the people should have a say.

Explanation:

When the first proper democracy was made it was at the start of America. The colonists broke away from the British rule due to being suffocated by their control. Once they did they needed to create their own government. They were fearful of having a ruler with too much control so they created a "Represenitive Government" basically a democracy. This later turned into a democracy, meaning that the people had a say.

whose power in the senate is equal to the power of the speaker of the house?

the answer i chose to believe is 'harmony'