In the Declaration of Independence, the king is accused of holding legislative meetings "at places unusual, uncomfortable, and distant" from their ordinary locations.

What right has become an important part of American democracy ever since this complaint was written?

The correct answer is the right of constituents to observe the workings and processes of law-making. People need to be able to watch how their government is working in order to support it if its actions are in accordance to the common good or protest it if its actions carry prejudice against the welfare of the people. Historically, during the tense years that preceded the American Revolutionary War, legislative meetings had become so contentious and vocally belligerent that British Colonial governors were too afraid to enact very unpopular measures. In order to avoid the confrontation, they began to move the meetings to locations that were too far or that had very difficult access so that American lawmakers would not be able to attend and vehemently protest the King's policies. Those who managed to get there would be too tired and too few to effectively protest against such policies.