after i'm done using an app, whether it requires net connection (4g) or not, how do i know if its closed or still running in the background? i usually just tap the home button and put the phone down. does that close the app or do i need to do something else? i don't want it to use up my data if it is still running in the bg. back in the days when i'm using a symbian phone, application does not close if i press menu or clear. by doing that, it just hide and continue to stay open in the bg, until i manually close each running application.