Final answer:
A major difference between the Articles of Confederation and the Constitution was the amending process. The Articles required unanimous approval from all states, while the Constitution only needed approval from nine states. Additionally, the Constitution strengthened the central government and provided for a national military.
Step-by-step explanation:
A major difference between the Articles of Confederation and the Constitution was that amending the Articles required all of the states' approval, while amending the Constitution required approval from only nine states. Under the Articles of Confederation, the federal government was weak relative to the states, while the Constitution created a stronger central government. The Constitution also provided for a national military, whereas the Articles relied on state defense.