Which of the following is a duty of United States citizens?

One of the key duties of United States citizens is to defend the nation. This responsibility highlights the importance placed on national security and the role that citizens can play in protecting their country, particularly during times of war or crisis. While defending the nation is a significant duty, it is part of a broader framework that includes several other civic responsibilities that citizens have.

Voting in local elections and attending school are important aspects of civic engagement and personal development, respectively, but they are generally classified as rights or responsibilities rather than duties in the strictest sense. Voting is a right bestowed upon citizens which allows them to participate in the democratic process and influence government decisions, while attending school, particularly in the younger years, is mandated for educational purposes but is not explicitly labeled as a duty under the framework of citizenship.

In summary, the duty to defend the nation stands out as a core obligation of citizenship, emphasizing the commitment of citizens to contribute to the security and well-being of their country.