1.When a request is made for, say, /pages/home, the Pages controller executes the code in the "home" action and then automatically renders the view corresponding to the action -- in this case, home.html.erb.
2.This maps requests for the URL /pages/home to the home action in the Pages controller.
3.When the order matters, use an array.
4.It's a test that simulates a browser accessing our application.