Final answer:
The 10th amendment was added to protect state power and limit national power in the Constitution.
Step-by-step explanation:
The correct answer is the 10th amendment. The 10th amendment to the United States Constitution was added to protect state power and limit national power. It states that any powers not specifically granted to the federal government are reserved for the states or the people. This amendment was included to maintain a balance between state and national authority, ensuring that states had the autonomy to govern certain areas within their borders.
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