A Green Card holder who is not a minor can file Form N-400, Application for Naturalization, to obtain US citizenship. Similarly, he must have become a permanent resident before five years and must have remained as a permanent resident in America for at least five long years.
Now, flat paint is (usually) a latex paint that dries without a reflective finish-that's it-the finish is smoother (imho) than chalk paint. Chalk paint really dries quickly and it has a rough texture to it after it dries. Many people use wax or poly-acrylic sealant on top of their furniture piece to keep the paint from peeling. So there ya go, my best explanation.
Choose your sheen based on how much traffic the area receives. Flat is a low-sheen paint with a non-reflective finish that touches up well and hides minor surface imperfections. It's ideal for low traffic areas, interior walls and ceilings. Matte has a low luster reflective finish that is durable, easy to clean, touches up well, and also hides minor surface imperfections.