I've had my Nexus 4 for a couple of days now and something is bothering me. I came from an iPhone, and although I know this was an issue too, it wasn't as noticeable. How do I keep the apps in the background from constantly running? For instance, I have whatsapp messenger, but I don't use it often, almost every time I got to my task killer it is running. How do I prevent it from running in the background if I haven't activated the app. Maybe this isn't an actual problem I should be concerned about but there are a number of apps that appear to be processing in the background that I would like to terminate.