Most Greek city-states did not have enough flat land that was usable for farming. They (the leaders) had two choices, they could fight other city-states for space or they could reduce their own populations. What did they do?

They fought other city's for space.

The correct answer is "The Carta Magna" and "The Petition of Rights".

The Carta Magna was a document issued on Juen 15th, 1215. It marked the first precedent for the limitations of the exercise of the British Crown's powers over the citizens which in this case were the Barons.

The Petition of Right is a constitutional document issued in 1628 which further limited the Royal Crown's powers by restricting non-parliamentary taxations, imprisonment without cause, and the use of martial law.

These documents served as a reference for the Constitutional Convention to elaborate the draft of the Us Constitution, as they proposed limitations to the Federal Government which was to be formed.