Final answer:
The Ninth Amendment was included in the Bill of Rights to clarify that there are other rights beyond those expressly listed in the Constitution. The Tenth Amendment delineates the balance of power, reaffirming that any powers not given to the federal government are reserved for the states or the people.
Step-by-step explanation:
The authors of the Bill of Rights felt it was important to include amendments 9 and 10 to address concerns that the enumeration of specific rights in the first eight amendments might be interpreted to mean that citizens did not possess other rights beyond those listed. The Ninth Amendment served to emphasize that the people have additional rights beyond those explicitly mentioned in the Constitution. On the other hand, the Tenth Amendment was crucial in establishing a principle of federalism by confirming that any powers not delegated to the national government, nor prohibited to the states, are reserved to the states or the people.
The Ninth Amendment ensures that listing certain rights does not lead to the presumption that other unenumerated rights are denied. This amendment indicates that there exist more liberties than those expressly mentioned in the Constitution. Likewise, the Tenth Amendment secures a balance of power between the federal government and the individual states, making clear that the federal government only has the powers that are provided in the Constitution, with all remaining powers belonging to the states or the people.