what is the process by which people from foreign countries became U.S. citizens
This site explains this process.
http://www.us-immigration.com/index.html?referrer=adwords&gclid=CKv7x7aj07kCFSJqMgod5WkAtA
http://www.us-immigration.com/index.html?referrer=adwords&gclid=CKv7x7aj07kCFSJqMgod5WkAtA