The response that best describes recent divisions and changes to political systems in the Middle East is:
The regime changes of the Arab Spring were caused by division and frustrations with the region’s political systems, which caused protests in the region.
This statement captures the essence of the political upheaval and shifts that occurred during the Arab Spring, which was marked by widespread protests against established regimes due to various grievances, including political oppression, economic hardships, and demands for democratic reforms.