Final answer:
A state constitution's function is to set up the branches of government and define their structure, duties, and the rights of citizens. It holds the reserved powers to manage intrastate matters and balance power with the federal government.
Step-by-step explanation:
The function of a state constitution is to set up branches of government. This includes defining the structure of the government, its duties, and the rights of the people. A state constitution has several reserved powers such as: regulating intrastate commerce, conducting elections, providing for public health, safety, and welfare, establishing local governments, maintaining a militia (National Guard), and ratifying amendments to the U.S. Constitution. Additionally, state constitutions also outline the powers not explicitly delegated to the national government, as per the Tenth Amendment, which ensures a balance of power between state and federal governments.