Correct answers
Actually closing all the applications can do more harm than good on an android device . The system actively manages the resources including keeping the applications you using most in a suspended mode for easy recall when you next need the application. If you haven't used an application for a while, its resources are removed from the RAM memory in favor of the applications you are using. If you close or shutdown all of the past applications you use , the OS is forced to load all the applications it thinks you might need.
To answer your question , it is the square button on the right side of the home button that lists all your recent applications. You swipe them off the screen to clear them from the recent list.
Actually closing all the applications can do more harm than good on an android device . The system actively manages the resources including keeping the applications you using most in a suspended mode for easy recall when you next need the application. If you haven't used an application for a while, its resources are removed from the RAM memory in favor of the applications you are using. If you close or shutdown all of the past applications you use , the OS is forced to load all the applications it thinks you might need.
To answer your question , it is the square button on the right side of the home button that lists all your recent applications. You swipe them off the screen to clear them from the recent list.