Explanation:

    The United States is a land of opportunity, which means that there are a lot of things that people can achieve (or do) if they want to. But some opportunities are reserved (or set aside) only for U.S. citizens. What can citizens do that no one else can? Only U.S. citizens can vote, apply for a federal job, run for office, and carry a U.S. passport.

    Only U.S. citizens can vote in city, state, and federal (or national) elections. This is both a right (something that one can do) and a responsibility (something that one should do). Many Americans choose not to vote, but they always have the opportunity to participate in elections if they want to.

    U.S. citizens can also apply for federal jobs (or jobs with the national government). These jobs are not available to people who are not U.S. citizens. Sometimes this is because of the risk (or the possibility of something bad happening) of national secrets (or important information other people shouldn’t know about) being given to other countries. Another reason that federal jobs are not available to people who are not U.S. citizens is that Americans want their taxes (or money that they pay to the government) to be used to pay other Americans and not people from other countries.

    U.S. citizens may run for office (or try to get elected (or chosen) for a political job by voters). This can be anything from the mayor (or elected leader) of a city to the president of the United States and every job in between. Often there are other requirements to run for office, such as age or residency (or the amount of time that someone has lived in a certain place).

    Finally, only U.S. citizens can carry (or have and travel with) a U.S. passport. Not all citizens have a passport. It is a document that we must apply for (or fill out a form to request). But all Americans are entitled (or have the right) to get a passport and travel to other countries. People who are not U.S. citizens, of course, cannot have a U.S. passport.