Final answer:
The fundamental principle common to both the Declaration of Independence and the Constitution is sovereignty resides with the citizens. This principle asserts that ultimate power and authority belong to the people, who have the right to govern themselves and make decisions that affect their lives.
Step-by-step explanation:
The fundamental principle common to both the Declaration of Independence and the Constitution is A. Sovereignty resides with the citizens. This principle asserts that ultimate power and authority belong to the people, who have the right to govern themselves and make decisions that affect their lives. The Declaration of Independence specifically states that governments derive their just powers from the consent of the governed, while the Constitution establishes a system of government that is based on the idea of popular sovereignty.