Flour is the primary ingredient of any bread recipe. It is the bread that we see. Flour contains gluten, a protein that provides for the elasticity, and the basic structure of bread. As the mixture is heated, the starch in bread sets, and adds to the structure.
If you are a U.S. permanent or conditional resident -- that is, someone with a green card -- the basic rule is that you cannot apply for U.S. citizenship (or apply to naturalize) until you have lived in the United States as a lawful permanent resident for at least five years.
This page describes the most common path to U.S. citizenship, which allows a green card holder (permanent resident) of at least 5 years to apply for naturalization. Other paths include: Green card holders married to U.S. citizens. Green card holders in the military and their family.